Call Todd at overton fisheries. He is local to South Central Texas and he is an all around good guy!! I would use the CNBG not HBG because you will need the CNBG offspring as the backbone of the food chain.
As for numbers, that all depends. Tell us about the pond, size, shape, depth, water source, water chemistry, secchi readings, age, what is in it now, do you get wind action, are you going to feed, are you going to use aeration, ect.
Then the experts will be able to give you a good place to start.
BTW, welcome!!
