Drew, you mention limiting the species due to conversion rates but let me add this.. The conversion and growth is only at it's optimum if the correct size of forage in the correct number is available at ALL times. That may require 15 different forage types to maximize the potential. you want no gaps (too small-too large) for the predators to get maximum return.
The YP and SMB to some extent in the cycle will eat the fry of the other.
Any route you choose will require some harvesting to maintain a quality fishery regardless of species, but I can tell you've put a lot of thought into this, and I'm sure it will be good to hear from those with many years of having this combination.
