[BrianG]

I don't think he's thinking that the ratio changes from forwards to brake, but rather the braking energy changes with gearing. Like if there is X amount of EMF on a given setup, but then you gear down (or up) X changes accordingly. I can see a lower geared setup generating more EMF on braking if the initial speed was the same just before braking. That would mean if the lower geared setup was at WOT before braking, then the higher geared setup would have to be somewhat less than WOT to have the same initial speed.