You cannot run this tire with a larger rim then a 12" and fit it under a mini tub no matter what you do to the lip. Tt that size, adding a 1/2 inch of wheel adds a half inch of section width and quickly make the sidewall to large. I just had to re do a pair of 13" rims that would not fit. I had to have them made into 12s.
As for that tire fitting on a 12" rim, Actually Michelin spec is done with a 12" wheel. Here is the Tire Rack page on Michelin PS2s
http://www.tirerack.com/tires/Spec.j...e1=yes&place=0
Up front a 285 / 35 / 18 would work and give you a real nice tire height stagger. Tire stagger is important and many screw this up. I cannot stand it when someone puts 18s on the back that are 26" tall, and 17s on the front that are 26" tall! it looks like the front tire is taller then the rear tires! The front tires need to be as much shorter as the rim, so if the rim is a 19 on the rear and a 18 on the front, the tire needs to be a inch shorter, at least!
The rears on this set up at 27.4" on a 19" rim will leave 4.2" of sidewall on the rears, a 26" tire height on the front on a 18" rim will leave a 4" sidewall. I HATE when the front tires have a taller sidewall then the rears, HATE IT! Did I mention I do not like that look?
Also, with this set up, you will have a consistant sidewall buldge that matches nicely from front to rear with a bit more buldge on the rear tires. The rears on this set up having a section width of 13.6" on a 12" rim and leaves a .8 buldge on either side of the rear rim. The front having a 11.3 section on a 10" rim leaves a .65 sidewall buldge on the fronts, which again is the look were going for.