What's the offset & backspacing on stock 2010 FX4 20" wheels? Are they 20x9 or 20x8.5 or 20x8?

I'm wanting to put the following on a 2010 FX4 SCrew that will have a 2" level kit, will any of these combo's fit w/o rubbing???

Ballistic Off Road Wizards 810
20x9 +30 offset 6.18" backspace

Toyo Open Country AT
305/55/20 (33.2"x12.4")

OR

Toyo Open Country AT
305/60/20 (34.3"x12.6")

Thanks!!!

 

The stock 20's up to '08 were 8.5'' wide with 6'' bs.

I would think that the 305/55 would fit no problem with that wheel, not sure on the 305/60 but I would be it close.

 

I believe the OEM 20's have 6.5 inches of BS. I think both of those tires will fit but you may have to do some minor trimmng with the 34's.