Responses:
+++ well, where I live (SE Kansas) a 5lb SMB is like catching an 8lb LMB, very rare, but is my goal. For HSB, 10 pounds and up is the goal.+++
Std wt for a 5lb SMB is 20” and 10lb HSB is 26”. Do you have any reported growth rates for your stocker predators (12" range, and HSB could be 15-20") at SMB starting of 12” and HSB about 16”??? Knowing some good growth rates for these predators will help you determine how well the predators are performing and the relative abundances of forage fishes. We could derive some reasonable numbers for this.

“+++ I do not want to mess with pellet food whatsoever. At most, I would like to fertilize in order to support the bottom of the food chain, which in turn supports the top, but if I pursue this I want to be very careful. I do have a 5lb bag of Pond Plus that I was intending on using early next Spring to start out with. Thoughts? +++”
If you are not going to feed pellets and you being in Kansas soil structure, then you might have enough natural fertility to achieve your fishery plan. Before you fertilize, I would check the alkalinity of the pond to make sure what natural nutrients are present so they can produce acceptable phytoplankton and zooplankton. The minimum alkalinity for blooms is 20ppm however I prefer alkalinity around 50-80 for best naturally produced blooms. Since you have experience with aquariums you should be able to use an aquarium water test kit to verify some basic chemistries.

+++ Would my idea to fertilize help support this? +++
I would not fertilize unless you have lower amounts of plankton and secchi disk water clarity greater than 4-5ft. And then I would be very cautious using standard dosages of fertilizer. Fertilizing ponds can be tricky and risky and not for amateurs regarding long term pond health and stability of the algal community structure.. One new fertilization philosophy is to have desired water clarity of around 3ft not the old school clarity of 16”-2ft. If you decide to fertilize I would use lower amounts each time to not develop the 2ft clarity. Secchi disk clarity does not really verify phytoplankton density. Secchi clarity is affected by silt-detritus, phytoplankton, zooplankton, and bacteria. I can help verify composition of suspended solids.
For more detailed new information about fertilization, listen to this podcast for a pond fertilization discussion.
https://www.buzzsprout.com/976324/8656547-episode-56-binding-nutrients-in-your-pond-and-lake?t=0

+++ With all this into consideration, a fully grown SMB and HSB 'should' be able to eat 4-5" BG/sunfish I'd imagine. I do absolutely get your point of it's more work and less gain with smaller food. I know with HSB at least, they will go nuts on whatever is available, at whatever size, and are extremely active. The SMB I would have to guess would be the ones eating the more medium size sunfish.+++
Point is if more energy is expended catching too small of forage compared to the energy nutrition stored then growth is not as good as it could have been. Fully grown SMB and HSB can probably eat 4”-5” sunfish but will they eat them when smaller fish are more abundant. Predators IMO will often eat mostly what they encounter most commonly. You will definitely get growth of the large predators eating lots of small fish, it is just my thinking the growth will not be optimum. Some reduced annual growth is much better than “hit the wall” maintenance condition.

+++ This is part of the goal, kind of haha. Since the HSB will be moving a lot and pushing food fish around, I'm counting on the SMB essentially eating out of opportunity since hopefully the fish will be on the move quite a bit due to the HSB, which expend a lot of energy whether they are eating or not. +++
SMB may not move around as much as you think due to HSB activity. I think SMB feeding activity will be in a completely different niche compared to HSB. You have different food items living in at least two different pond areas – open water and littoral niches. My understanding of SMB is they tend to be a more sedentary habitat oriented fish.

+++ Yep, I will be supplementing the adult BG/sunfish during each summer most likely. I don't anticipate a lof of the initial offspring living long enough to get big, but the initial stockers should be around for a while since they're too big to get eaten, by the fish ;-) As far as the initial HSB and SMB, I'll be keeping track of their progress through catch and release and keeping info in a database with their tag number. If they start getting stunted or look unhealthy, I will remove as necessary. +++
It will be you as manager to monitor sunfish and shiner densities and then respond accordingly. Frequent surveying of the forage fish numbers will significantly help you evaluating fish densities and balance. This is where feeding small amounts to the forage fish can visually help you assess their sizes and numbers. Other ways to do this is trapping and seining AND keeping good records of the efforts, methods, and catch results for comparisons and monitoring of annual forage amounts.


+++ This obviously supports pellet feeding, but this is also why I'm stocking less total predators and a variety of well-established forage before adding the predators.+++
Fewer stocked predators and planned numbers will IMO be great growth initially but as these predatory fish grow they eat more and expect forage fishes to significantly decrease. Again, regularly monitoring forage sizes & densities will be important because you are not feeding pellets. You may need to use other monitoring methods rather than visual. You will always need ample forage to keep the predators growing or at least in good body condition.

+++ Absolutely. If I have an over-abundance then I would have to contribute that to the predators not keeping up, right?+++
Yes -- an overabundance of small forage including shiners and scarcity of large BG are good indications that the predators are not “keeping up” with recruitment of forage. In this case several main choices are to: A. add a few predators, B. manually thin the forage fish, C. do nothing if predators are performing well, Your mixed sunfish blend of primarily adult male and female BG, adult RES, and some adult hybrids mixed in (no GSF) could produce some interesting results as far as sunfish density and their top end sizes. With your plan and access to larger stocker fish, if large panfish are not common enough and pond has lots of small forage, I would supplement with some adult sunfish by removing several small forage individuals for each added adult sunfish. Be aware implications of an overcrowded fishery.

+++ Yep, which is why I feel it's so important to stick to the 20 SMB and 5 HSB, and just try to maintain that number as long as I can. I know the SMB will spawn and there will be fish I can't see or catch, but I will be closely monitoring the overall health of the predators.+++
Your predator density and choice of forage fish will be a good basis starting point and for study. As predators add poundage then you may need to reduce number of largest predators when their Relative Weight decreases. My experience is catch and release results in premature deaths of larger predators. Just because the fish swims away does not mean it lived. Be aware the catching HSB when water temp is around or above 80F significantly decreases the chance of this fish surviving after release.

I hope you return to this thread on a regular basis to educate us about the progress of your interesting fishery.