E85 the right way

Not exactly fossil fuel free, but less carbon intensive for sure. I found out there's a pump close to my home, so naturally, i want to convert my 7th.gen Celica GT to flex fuel. Obviously not buying an ffv vehicle since those are mostly trucks and suvs. The only cars that im aware are flex are the focus and dart. Both are heavier and more expensive than my celica. I didn't go with a prius either because i wanted a car that'd be fun to drive.

Anyhow, my goal is to reduce carbon emissions by switching to renewables.

I've heard of a few ways to increase ethanol tolerance:

1) is to use blends between E10 and E85 unmodified. The stock ecu can compensate up to like E35ish. I've gone to E18 so far with zero issues, but I'll be increasing the blend with future fill ups.

2) slightly larger injectors. Small enough to run E10 without going rich, and large enough to run higher ethanol blends. Might make it to E85. Might not.

3) e85 kits. The eFlexFuel kit in particular looks nice, in that it measures blends and changes trim/afr accordingly. Obviously doesn't adjust timing or compression.

4) microsquirt piggyback. Use a megasquirt and flex fuel sensor to tune for e85. Probably more efficient than the AFR kit or injector swap. Way more work. Dyno time isn't cheap either.

Standalone ecu isn't an option due to emissions, even though ironically that's what I'm trying to improve!

Has anyone tried one of these methods? What do you recommend?