HSB are definitely not unrealistic because of their inability to reproduce, ease of removal, and affinity for artificial feed. You just won't be able to get very many of them to thrive in your pond. George Glazener had an excellent thread previously that discussed how to get higher quality HSB from your fish provider. We need to access that thread. You could start with 50 fish early, (ten pounds total or so) and add or subtract over the following two or three years based on body condition of the fish, and modification of your goals over time. Even twenty fish in a pond that size will have an ominous presence. You'll like them. Will your pond be subjected to very high air temps during the summer?

Holding a redear sunfish is like running with scissors.