I better put an acronym for Specklebelly sunfish on our acronym thread in the Common Pond Q&A archive. I will use SBS speckle belly sunfish. I decided to use SBS instead of SSS because these hybrids could be produced not just in the south.
Rain events on un-full raw pond sides will crate muddy silt laden water runoff in the basin. Plus muddy water with most clay from track hoe work will take months to settle enough to create water clarity of 2+feet. Expect fairly cloudy water until the pond is full.
The more rock lined shoreline that you can create especially on prevailing down wind shores the clearer the water will stay in the pond. This is by having less shoreline wave erosion. Ponds like rock cobble lined shore in my area have 3 to 8ft of clarity. Good clarity allows more efficient predation of small fish. Plus clearer water of 2+ft allows or more natural productivity - planktonic and attached growth aka periphyton.
Newly filled ponds quickly develop a primary productive food chain. The exposed soil almost always has some nutrients in it to grow terrestrial weeds, thus phyto and zooplankton will also quickly flourish in this basin of water providing by spring the water clarity is 16"-24"+ to get optimum productivity. Invertebrates such as aquatic fly larvae have already been laying eggs in the basin since it first had water in it. Thus by spring the pond will have myriads of tiny foods available for small fish. Also some pellet feeding will somewhat enhance the pond fertility. All organics going into the pond contribute to nutrient increase.
IMO you are over-thinking the pellet hand feeding thing especially if you are only planning to feed around 125 panfish and minnows. Around ½ bag of pellets should last about all summer and fall. See if you can buy this limited amount of appropriate size of pellets where you get the panfish. Pellet hand feeding could be done 3-4 times a week, although fish growth would be a little less than optimum. Ideally hand feeding should be done 5-6 times a week to get close to best growth. But remember 125 small fish will not eat much more than 0.75 cup of pellets per day. Toward the end of late summer they may eat 1-1 1/4 cups per day. In my experience hand feeding 5-6 times a week for 4"-6" YP stocked in April-May post spawn will grow to 7"-11" long by late fall. I get that to happen regularly in new ponds when 4"-6" are stocked with FHM.
If this concerns you about not enough foods available then stock an extra pound or two of FHM. YP recruitment can be significantly suppressed by placing small 5ft- 7ft twiggy tree branches along the shoreline prior to the spawn. Then remove all egg ribbons observed. One YP egg ribbon from an 8"-9" YP will have 8,000 to 15,000 eggs - more than enough hatchlings to populate a small pond.
Primary predators of SMB-HSB could easily be stocked the first fall especially for the SMB. Waiting until spring IMO has little benefit (see below). Plus locating SMB in spring is very difficult because they are very often sold out in fall. SMB are not prolific often have sporadic hatch successes for fish hatcheries thus the spring shortages. I would stock whatever size SMB you can locate. Plus you are not needing very many so cost is not a big factor so you can stock larger 6"-8" SMB if desired and IF you can find them. Stocking the 6"-8" smallies becomes a little more important if you have a YP-RES spawn that spring so these larger smallies can thin the herd of panfish. If you have no perch spawn this spring then smaller fingerling SMB are good for a fall stocking. HSB as juveniles 4"-8" are most commonly available only spring in my locale.
"" What about the hybrid BG?"" Specklebelly as you are referring to. To my current knowledge it is not fully known which parent sunfishes are used to make this Specklebelly by Malone’s Fish Farm. The specklebelly was discussed back in 2017 on this forum.
https://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=462692Childers in his study of Hybridization of Four Species of Sunfishes (1967) found that a number of different kinds of hybrid sunfishes are not sterile and can produce sometimes “abundant” F2 and F3 generations and can be backcrossed to the parent species and some will outcross to nonparent species. It all depends. Thus if you stock them I suggest that you monitor their offspring abundance each fall or spring. Note that SMB and HSB might not be able to adequately crop abundant hybrid young of year (YOY). Adding more HSB to the pond if needed will help crop small sunfish hybrids. Then be prepared to crop their numbers via seining or fish trapping. One can easily remove numerous small sunfish and YP with wire mesh traps. I can easily catch 20-50 small young of year YOY YP from each trapping session in fall or spring pre-spawn by using just two homemade fish traps ¼” and ½ mesh.
