FWIW, I have been flying my 12 for 210 hours in South Florida, and am tied down. It gets hot to very hot! I have a cover for overnight tie-down, but do not cover the canopy for the lunch trips, 1-2 hours on the ramp. I use Costco 93 exclusively, and to date, have never experienced and throttle hesitation, vapor lock, or similar issue.
Steve at BCT
Flying a built ELSA (When the President isn't in Palm Beach!), just passed 215 hours.