Originally Posted by RavSpec

Assuming at A disk, that's 20x10.0 +12mm spec wheel you got. Yes, that's identical stance with 20x9.5 +6m. BUT since you have to add 12mm spacers, so you are at 20x10.0 0mm offset.

That's 90mm lip barrel (outside) and D barrel inside.

The easiest solution is to change the outer barrel from 90mm to 84mm.

That will put you at 20x9.5 +18mm. Add 15mm spacers you will be at 20x9.5 +3mm which will be closest spec to what you want.