72MachOne99GT

i have something similar posted about this in the gereral tech area, but im sure alot of the old car guys dont check there so i was hoping i could address the rest of you with this topic.
I'm looking at putting some cragers, or somthing in a 15" on my 99GT since know it will be cheaper, more unique, and pretty cool with a rim and more tire than on new cars.

so my question is,, assuming i can find some 15x's and they will fit my car and all,

what's the widest size of tire that i can use to fit each wheel?

for now, just focus on 15x10 and 15x8.. <---back/front
(i ahve already been told to go with a 26" height to keep from needing to recall the speedo)

i want the widest couple of sizes i can fit on each rim..

thanks alot guys in advance