Here is my 2 cents-I have 2" of clearance between everything, wheel well opening and frame. I use the rubber stop that is Incorporated in the coil over as my stop. I set the ride height where it has 1 1/2" of travel before it makes contact with the stop, the stops are generally tapered for a progressive interference. Then I use a coil spring that gives me a compromise between ride quality and travel. I use the longest shock I can get in there for the dampening. I have never bottomed out any of my cars using this method. Maybe I have just been lucky on the bumps I hit
Ken