Would someone please explain the difference to me between Michelin XL, XCL, XZL, and XS tires? Also, will 16.50s fit on 109 Rover rims and what is the difference between 7.50s? I have a spare XCL on the bonnet spare on one of my Rovers. I like the look of it. Are these good all around tires? Any other tires suggested for 109 SW. I like the stock size and do not want wider or taller tires than required. Lot of questions but help would be appreciated before I plunk down my cash for tires. I drive on highway(not interstate), sand, and sometimes mud.