Still thinking about this mod, but also still contemplating the requirements.
The back should be easy to figure out, the wheels only have to move mostly up and down in the wheel wells, so if they clear, they clear.
In the front, they have to move up and down, as well as doing so through the full turning radius. While I admit those 15s look good pointing straight ahead, I'm a bit scared thinking what might happen on a big bump at full lock.........
Thinking maybe 15 back and 12 front might be a safe bet. Think I'll let you guys be guinea pigs for a bit before I decide :-)