Need to Validate wheelfit tool measurement
 

Attached are the pictures of the Wheefit tool with pictures showing the space on each side of the tire and the tool set up.

I'm unable to verify hands on as I'm in Germany and the car is in NY with my father doing the measuring/fitting... and getting frustrated.

I do not know the actual thickness of the "L" leg. From the picture I'm guessing 0.25

315/30/18 Falken Azenis
Vintage Wheel Works V40
18x11 wide
I have to use a 12mm wheel spacer 0.472 to give me caliper clearance

My math is 0.50 for the mounting flange thickness, 0.25 for the "L" leg thickness.
Subtract both of these from 8" (straight side of "L")
That gives me 7.25
I now have to subtract 0.472 for the spacer that is need for caliper clearance.

This makes my over all back space 6.778

It looks like I can suck it in a little bit more so I'll say 6.75 is what I should order for BS.

I decided to verify in AutoCAD... I was wrong
I need to add not subtract the spacer.
Ordered 7.75 BS giving me an effective 7.25