...Since we can't actually view alternate realities the next best thing would be running a very sophisticated war game simulator where the F4F is replaced with realistically nonwankish appropriate to the situation number of F5Fs and then can we analyse the results to see if it would have been a better choice or not.
I'd also want to run multiple simulations with a 4 & 5 mix. Say a 20% F5F, & 35% F5F. Not sure how the mix would fit the carriers, but land based squadrons like the Marines would benefit. Perhaps with 100% 5s.