Asking of course since my RF tire wears about 3x faster than the rest
if this is true, then something is out of spec.
have you had it aligned?
has it been in an accident?
is something bent?
rotate the tires, it is a must.
regarding your question, the AWD system needs all 4 tires to be within 1/4 inch in circumference. so rotating the tires is a must. front to rear is a must. the front wear faster. put the tire with the most tread on the RF. i would assume this would be one of the rear tires, but check them.
you can get a tread depth gauge for a few dollars, so if you do it yourself you will get it right. or just have shop do it and have them check the wear.