Another rear tire size question and advice needed.

Do you still need me to pull a wheel and measure my spacer? Im sure that we pretty much have the same set up (8.25, 15x8(4.5" bs), 255/60-15).
You can probably figure out what thickness you need now that you have a 255 on the wheel.
Iam thinking that like you...a 3/8 spacer and the 1/4 I have will give me 5/8. Hopefully that's enough..ty ty for your help