I agree with Bill on the trapping. Also realize that time is an importaint factor. Greens directly compete with bass for food. They have a much larger mouth than a bluegill and are voracious predators. Bluegill and greens have benn crossed producing the infamous "Georgia Giant" (that is my opinon on the origins of the georgia giant) the problem I have seen with people that have used hybrid bgs is that the f1 crosses are very good but future generations revert back to green sunfish phenotypes. So after a few years all the hybrids are gone and you are left with mostly green sunfish genetics. The longer you wait the more hybrid sunfish you will have in your pond and the harder it will be to avoid option 3.