scampbell,
Google "Guidelines for the Culture of Bluegill Sunfish". Everything you want to learn is in there. FWIW, BG do not handle well below 1" in length and in a culture pond that maximizes production of individual BG, they usually stop growing or grow very slowly at 1.5 to 2 in in length which occurs in about 45 to 60 days. IMO you will be better off stocking them between 1.5" and 2 " and allow them to attain 3" sizes in your much larger lake. Just stock them numerically strong enough to have the survival required to meet their recommendation.
If the biologist recommended stocking the BG at >3", why are you recommending that the OP stock BG smaller than that size?