Every ridden in a stiff lifted 4x4 truck? Now that's a horrible ride. The key to a good ride is springs in the seat. It's amazing how much that helps.
It's more a matter of spring rate and suspension travel than the weight of the car. If you want a T tall with lots of travel, then you can go with softer springs. Mine is pretty low, so I can't afford a lot of travel anyway, or I'll bottom out. I don't think the length of the radius rods are going to amount to a hill beans worth of difference in ride quality, not when you talking 4" or so of total travel.
If you want to get real creative, go with air bags!
Good luck with your project and start a journal