George, Nancy and I had our suits made by Z Leathers in light colors - on purpose. Vintage appearance is all fine and dandy but I was to be awake and alert to enjoy the colors. They're two-piece zip-together suits that allow us to wear the pants, therefore partially dressed, but hot the top - staying cool 'til we're only a few vehicles from next (BTW, we do not race at AMA events so don't know the routines there).
But of most importance for our comfort: We both have full-body Kevlar underwear from the Draggin' Jeans company. They're a coarse-weave mesh that is surprisingly good at letting breezes in (when not wearing the leather jacket). Yeah, we looked kinda funny in long-sleeve yellow thermal underwear (or so it appeared) but dangit, we were very cool.
Of course there was the time that Nancy crashed and they tried to cut her underwear off. That created quite a stir in the ambulance, I'm told -- "WTF? This stuff won't cut!! Get some tin snips!!"
Other stuff: Russ O'Dally, chief bike inspector back a year or four ago, would walk around to his inspectors (me and others) and ask "When's the last time you peed?" If you hesitated or said a time more than an hour or two ago - - he'd hand over a bottle of water and have (us) drink it right then and there. Prevention!!!!