What does seat tilt have to do with hands?

I'd check stem length, and if you are on riser style handle bars ( as comapared to drop) check handle bar width and rise. Gel glove may help.

My experience is that it can be the staticness ( stationary) body position that causes numbness. To this day, if I road ride on my mountain bike, I go numb on the right side, but it never ever happens on the trail because of the dynamic nature of mountain biking.

Irulan