Does anyone know what the # inside the rims mean?
I recently purchased 20" CONCEPT ONE CSM-001s.
​​​​​​2x 8.5" for front & 2x 10" for rear (staggered). My car is RWD boring Journey coupe. I assumed the offset purchased them from said the offset was 38 however looking at the inside of the rim 38 is the ET. Inside both size rims it shows 16 on one spoke and 17 on the other spoke with what looks like football laces.

​​​​​​Looking at the rims there is no way these will fit without spacers so I purchased 25mm spacers x 4 + wheel centric hub rings.This makes me think the front rim will sit flush by measuring the stock rim and what it's mounted to.

​​​​​​However since the back tires are 10"s (rather than 8.5s) these look like they will stick out way too far. Any recommendation on which size spacers for the rear?

Also what does 20x8.5J and 20x10J mean?
I've searched the forum and there doesn't seem to be much help besides recommending 19s.

ANY HELP WOULD BE GREATLY appreciated before I purchase tires!
Meanwhile I will look online to determine the calculations to determine offset.

 

Also what does 20x8.5J and 20x10J mean?
20 is the wheel size. 8.5 is the wheel width.