350 is already a very good amount, and way overkill according to those who preach 50-100 grams. It might be enough to maximize everything for 99.99% of bodybuilders. But then again some heavyweights might do a bit better on somewhat more. The absolute biggest freaks often sit at maybe 500 grams and a few have gone over. Often bodybuilders find the optimal spot by instinct. I remember Milos had told Nasser to eat like 450 but Nasser went with 600 and when he made the switch Milos said he put on a shitload of stage weight. And we know Milos likes to credit drugs but here he gave a lot of credit to the protein. Of course Nasser liked to say he ate 80 grams of protein a day lol.
Jay Cutler 600+
Kai Greene was at 700 when he won all the time in 2008-11 or whenever it was
Kai Greene diet:
16 oz steak, 12 egg whites, quart of white rice
2.2 chicken breasts, turkey burger, pint of white rice
16 oz salmon, 6 egg whites, large green salad
4.16 oz steak, 2 sweet potatoes
16 oz salmon, 2 cups oatmeal with raisins, cup of corn
shake 85 grams of protein, cup cashews or avocado
16 oz steak, 2 cups mixed vegetables
= 700+ grams protein