The weight difference is minimal same as the 1.5" tire size difference between 33s to 35s. Go 35's.
I'm up in KC and wheel in Clayton and Disney. Though now, I tow my Jeep to wheel those places. Steepest gear is associated to the front D30 at 4.88s. That's what I run. Its a 3-sp auto and does fine on flat land. Any slopes or wind, forget it. It slows down 3-10mph and at times, I have to push the pedal to take it out of lockup. Its a tired auto so it does fluster back and forth to 2&3. If you regear, look into lockers. Lunchboxes are not hard to do, but case lockers require the case replacement, thus regear setup. Do it all at once.