Are you sure they are 8.5j wide not 8j?
If I was having a stab at the numbers they look like a square set up 4 x 8j & et somewhere between 40/44
You have 225-40-18s on them but your pal wants more rubber.
I see no issue going 245-40-18 on the rears & adding a 12mm/15mm spacer would increase the staggered appearance.
Fronts look OK as they are in your pic but if he must have more rubber he could go 225-45-18 or 235-40-18.
I like the wheels , not unlike my Veemann FS34 8)