10.5x26..is ok,but i like the tires up in the wheelwell.10.5x27... with the 27 you may need to trim some of the lip. your best bet would be to measure BOTH sides ( one may be smaller )or have a tire shop do it,and see what fits.once they're mounted, there's no return.
also remember, the manufacturers listed size may be different than stated in the books.
you should have 11" from the inner lip to the inner wheel house and 28.5" front to rear wheel arch.(slicks grow)