Connor, I wouldn't sweat the GSF. Left alone without a predator, any sunfish will spawn and flourish. There's not much way you can eradicate them without chemicals. The bass, if you stock them, will eat them and cut down on their numbers.
However, the GSF only spawn annually and, over time, the bass will run out of forage. Bluegill will spawn 3 or 4 times per year.
If it were me, and it's not, I would stock about 1,000 three to four inch bluegills and get them started. I would simultaneously stock about 100 4 to 6 inch bass. Within a couple of years you should have a fairly balanced fishery.
