Okay, what size wheel spacer would I need for a factory "canyon" wheel to match the backspacing on a black rockcrawler? I think the rockcrawler is 4" but I don't know the canyon wheel's spacing. Thanks.

I think 1.25" spacers would give you what you are looking for.

most steelies are around 4" of bs, so indeed like chris-j mentioned -> a 1.25" wheelspacer will give you (about) the same bs with a stock Canyon (5.5" bs)