I was one of the first to switch to E85 back around 2006.

Buy a good E85 carb (it'll pay for itself in fuel over race gas in less than a season).

Set the fuel pressure a little lower than gas and go have fun.

Its that simple. I was fortunate enough to win quite a few big races on that stuff. I never drained anything ever. Ran a Mallory 110 with no regulator and eventually a 140 with regulator when the 110 died after many year s of service. On COLD mornings give a shot of gas (squirt bottle) to save your starter. Always stage at 160 or warmer. When done for the day let engine get to at least 200 before shutting down. Dewpoint imacts dial-in more than temp. Fine tune with air bleeds rather than jets. Rinse and repeat.

Dont overthink it.

I switched to Alky this year because everyone told me how much better it was. After spending thousands to upgrade I'm still waiting to see that payoff.