I don't know how much room you have, but a slightly bigger tire would help absorb the jolts and be much easier on the rims.
I weigh 250 and use 25mm tires & 32 spoke wheels, but I tend to have rather smooth pavement.
A 28mm tire with a bit lower pressure would give you a much better "squish" factor.
36 spokes on the rear wouldn't be a bad idea.