A lot of smart people on this thread so going to throw out another scenario.
Unbound is happening this Saturday. Alexey Vermeulen, who rides on ENVE wheels said he feels at the speeds the pros will be riding that aero wheels still matter and he will like run Enve 4.5s likely with a 40 or 42nm tire rather than the light and more compliant, but non-aero G23.
My understanding is if you mount a 40 or 42 on an aero wheel like the 4.5s, that pretty much all the aero benefit is negated. Or is there still some benefit in a situation where the pros may be in the 20 - 25 mph range at times.