How to solve preflop in a unique spread limit game

What tool(s) should I look at to solve a spread limit game with a betting cap? I live in a state with a $300 max bet for any bet. There is a bet and 3 raises allowed on each betting street. So the bet amount is capped at $300 and each street is capped at a bet and 3 raises (The big blind or straddle counts as a bet).

I play a $5-10-20 game with these rules and would like to solve and see GTO solutions. I have piosolver which I believe I can use to solve for this game postflop, but what can I use to solve for it preflop? Or has this been done and I can see solutions for this game somewhere?

Thanks.