Wheel Offset
 

Hi
I have a 2004 Ford F150 Regular cab 4x4 with 5.4.and 2 inch front lift. I'm looking to upgrade wheels and tires from stock.
Looking at 275/65/ 18 tires on 18x8.5 wheels.
Different wheels have different offsets and not getting much help from sellers trying to figure best offset range for my needs.
Want to keep the tires/wheels inside wheel wheels and not sticking out.
Any help or advise would be appreciated.

the stock backspacing is 5.5"