Welcome, Ontario!
I think we're now down to the point where I can only give my best guesses, and I haven't seen the water body. So, take everything with a grain of salt. However, if it was me, here is what I probably would do.
For the panfish, I like to try and shift the populations toward larger individuals. Thus, if your harvest strategy is taking out the biggest ones, that may be counter-productive. Male bluegills mature at smaller sizes when the big males have been removed. Once they mature, their growth slows down and they are not likely to get as big. So you want to favor 8 inch and longer bluegills. I haven't worked much with rock bass. However, as with the other panfish, I think having the big ones would help suppress the small ones.
So, what can you do to thin the small panfish? Well, you might try doing it mechanically - with nets or seines. Your lake is not that big, and you probably can have an effect. Put the big ones back and remove the small ones. However, it's generally a lot easier to have predators do the job of thinning for you. Let's run through your predators. I already mentioned that I don't trust smallmouths to be a good control for panfish. However, the bigger ones certainly eat fish and can help. Your best predator on the small bluegill/rock bass is the largemouth bass. If you know for a fact that they don't reproduce and survive well in your lake, then I really like your idea of maintaining a population with occasional stockings of adult or subadult largemouths. They probably need to be at least 10 inches long to survive after stocking. The 10-12 inch largemouths will really pound on the 1-2 inch bluegills and rock bass that are spawned each year. They�ll reduce panfish abundance, panfish growth will increase, and you�ll get bigger panfish. As long as the northern pike numbers are not high, they can be a good predator for you. However, northerns like to eat big prey, and they may compete with you for the big panfish (given a choice, they like prey items that are 33-40% of their own body length). If you catch a 10 pound plus pike while angling, I�d say it probably is best to remove it (fillet out those y-bones and have a good meal!). The 20-24 inch pike will do more for your current lake management needs. If they northerns start reproducing and become abundant, then you'll need to crop them down too. Too many northerns is a BIG problem.
I believe that I would keep up the harvest of small smallmouths. I say that for two reasons. First, as I already mentioned, they are not all that piscivorous at small sizes. More importantly 15-20 inch smallies are so darn much fun that I'd want them in my lake!
It sounds like your smallies will overpopulate and stunt without selective harvest of the small ones. That is my most common management problems with smallies in ponds and small waters around here.
OK, I hope that helps a little more. I tend to think of pond management in longer terms than a lot of the pond owners at this site. I�ve got one pond I manage that is about 10 years old. We introduced bluegills into that water about 7 years ago, and we caught our first honest 11 inch bluegills out of that pond this year. Some things just take time!
