there are easy ways to lose lift from the rear (shorter shackle, flatter leafs, etc) and easy ways to add lift to the front (coil spacer, stacking coil isolators) so just get the 4.5 and see how it sits.
with a 4.5" lift, fender trimming and bumpstopping you can fit 35s.
the biggest thing is 4.5" is really pushing the ride quality with short arms, and if you go even higher it starts getting real bad. i used to have 4.5" coils and an extra 1" from some stacked coil isolators, the ride sucked, but it worked.