Justin, is that 6" of lift on your red truck?
It takes more lift with a live front axle than with IFS because the IFS doesn't move at all. You can fit a larger tire with less lift, like you did on your 88 with IFS, because the tire really isn't going to move much up into the fender. You have a lot more flex on the SAS, and thus the tire is going to move more into the fender.
Obviously, this is all dependent on bumpstops and springs, and all that, but as a generality, it holds.
Baby Beast 2- 1999 4Runner SR5
Baby Beast -1987 4Runner SR5-Gone, but not forgotten