I like how you think, but I wonder the same thing about the overflow carrying ample amounts of FHM's to the main pond. "Ample" would mean enough to substantially feed the main pond fish AND enough to keep the forage pond from overpopulating.
I have though about this and pondered putting the pipe in as a drain instead of an over flow and just letting the whole thing go to the main pond in the fall and restocking the forage pond with breeders in the spring.
I am contemplating this with a 1/10 acre pond because I have a catch basin of that size uphill from my pond that could easily be de-mucked and deepened. It may just turn into a seined forage pond, but a guy can dream can't he?
