1) If we were to pick one single flop cbet size for all spots, which one would be the highest EV?

Based on an article by gto wizard, it seems for river it would be 50% OOP and 75% IP.

2) The same for the turn, which would be the highest single EV cbet size for all spots? I couldn't find any information on flop and turn.

3) How bad are we cbetting 1/3 bet size all flops as a default? Anyone here does that? How much EV would we lose compared to a complex strategy? It seems for the river it wasn't that much.

I have checked some information by gto wizard where in most type of boards, 1/3 bet size is the most recurrent size for either pure or mixed bet size strategies.

Monotone, paired, straight, rainbow seem to highly prefer it.

Even IP and OOP 1/3 seems more used overall than bigger on unpair suited flops.

Thanks!