The struggle is real!
Do you have the 2618 or the 4032 pistons? If you are still exploring alternatives, I have had excellent luck with Wiseco in another vehicle. It's 12:1 compression, 33psi of boost, roughly 900hp, for several years now. Semi-daily use and multiple passes, it's a damn good piston! No pepper on plugs, E85.
Remind me, have we talked about this issue with the Speedmaster heads? I can't remember if you're already aware or not - they don't machine the rocker shaft stands properly, and it causes this exact issue. It has resulted in many broken engines in this forum, including mine.
Sucks that E85 isn't readily available for you. It's a godsend of a fuel... Hopefully you can be happy with the meth injection.
Good luck, brother.