I don't trust using reference points on the rims. Unless they are new there is a chance there is some run out. If away from the alignment rack I use a plate held against the wheel face with a magnetic adapter. Sometimes I bolt the plate on to the rim using some standoffs I make so I don't have to hold it in place. All of the digital gauges are sensitive to vertical alignment making it dicey to get repeatable measurements at times. Being ever so slightly out of vertical can change the camber reading by one or two tenths and drive you absolutely batty. My favorite gauge is the Intercomp 100005 as it includes a bubble level for getting the orientation correct. Expensive but worth it. I have a Smart Camber gauge in the rafters somewhere if anyone wants it. I'll let it go away for very very little. Make offer.
Mark
I was thinking of something along the lines of a plate as well. Hang it off the lugs or something Going to see if Johnny D can fab something up.
Thanks for sharing the tip about the vertical alignment. I was noticing that also and didn't understand why it was changing. I was watching the numbers change as I tried to position at the same point on the wheel lip but didn't think of that.
How exactly does that Intercomp work? What does it attach to? I thought about buying one of those at the time that I bought Strings from you but couldn't figure out how to use it by looking at it and saw posts on here and the old site about the Smart Camber.