I would begin feeding immediately. You need to feed utilizing a high protein feed. Feed that is at least 40+% protein. Aquamax 500 is a good size and protein %.

When stocking a new pond, you can stock the smallest size fingerlings available for both CC and HSB. However, I would look at obtaining 6"-8" or even larger fingerlings if fall stocking to ensure I wasn't getting runts of that year class. By fall, good growing HSB should be 6 and really 8"-10" in size. CC should be 6"-8" as well...

I would call both places and not just rely on their websites and inquire as to what they have available. Many places are very anti HBG. It appears Schultz's is in particular. So they may not carry them. HBG are for very specific management purposes, but excel in that area.

If for some reason you cannot obtain HBG, there are a few options. Feed trained YP are one of them. Although different in many ways to HBG, they could still fit a similar role. RES are illegal to stock in PA and are too far north to most likely do well, or I would suggest them. I would not stock pure BG as they would be difficult to manage and most likely stunt with just HSB and CC preying on them in your situation. You could also look into have some redbreast sunfish(RBS) shipped to you. Although, they do not reach as large a size as BG or HBG, they will still push over a pound and pound for pound fight better. Plus, they can be purchased in a very cool golden color morph. They are not overly prolific and are a bit more fusiform meaning the CC and HSB would have an easier time preying on them as compared to BG.