Have you sighted your eye and compared against the column?
I'm going to be hopefully doing experiments very soon regarding wheel depth in relation to chassis.
To do this I have three plumbobs, and the necessary two pairs of blocks for leveling in both axis.
I sunk some cheap magnets into them, but tape would do fine...once you've found nice spots for them to go.

The third plumbline sits on the bolt heads

And just like the blocks, keep the line still, although as close as you can get is better.

A
A backlight can be useful

I've not got back to doing upper wheel protrusion experiments...ones whats worth a damn so far,
but not noticed any difference really, although my machine wasn't running smoothly,
so keen to have another crack at it,
perhaps it will make some difference, what I guess would account for tire edge wear for example,
that will have to be revisited also.
Should it be possible to match to the guidepost, I don't know, perhaps it might be a fix for something not too far out?
Hope that helps some, well at least give more of a clue regarding by how much.
Tom