I am going to say that I am 99% certain that the RES is a female. I base that on the urogenital pore and overall appearance ... so I think you did good in selecting a female for your project. Hope you find success this year and get a crop of hybrid little ones. I fish a pond where 9" lepomis are fairly uncommon. When I catch one that size it is usually a BG-RES hybrid.

It isn't what we don't know that gives us trouble, it's what we know that ain't so - Will Rogers