You got the numbers to figure it out and I'll tell you now 6mm is not even close.

15x8 with 4.5" backspace fits.
15x8 with 4.92" backspace does not fit.

Wonder what the difference is? .42"
Wonder hot thick a spacer you need? .42"
Wonder how many mm .42" is? 11


BTW, I like the looks of those rims.

They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.