Think this is right, basically you’d have to weigh well over 100kg before the Neo wouldn’t be able to provide enough resistance to accurately simulate the 16-17% maximum gradients in Zwift - and that’s assuming you’re at 100% trainer difficulty. Obviously anything lower than 100% is easier for the trainer to simulate anyway. You only need to adjust that slider if you want to, the realism isn’t dependent on your weight in this context.
I’m sure @Shane_Miller_GPLama will correct me if this is horse plop.