Pond Boss Forums INTRO Questions & Observations HBG breeding question

Here is what I think I know about HBG. The perhaps grow faster, but not necessarily bigger than regular BG. They have bigger mouths and are more aggressive. And while they tend to me 90% male, if they do reproduce the offspring can be less desirable green sunfish.
So, why not cross BG with RES, PS or CNB so that the outcross would still be a desirable fish? Are they more closely related so you'd have less hybrid vigor? Is one of the desirable traits of HBG their mostly lack of reproduction? Do I ask too many questions and am I giving clues to Bruce's top secret breeding program?