Another sway bar question

[RKS0069]

Hi!
Trying to get my sway bar mocked up. '82 c30 front end on a '62 1500series frame. The dreaded Xframe! So I have Early Classics 1-1/4 bar and their stock height brackets. Bar was ordered for my '72 C-10 but I'm going to use it on the GMC instead. GMC will have new stock height Moog '82 c30 replacement springs.
So my problem is I don't know exactly where to drill the holes for the frame bracket. I was hoping it would line up with one hole that is already in the frame but alas it does not, it seems to be about 3/4 of an inch off. There is obviously no weight or springs for that matter. Is there a chance you guys with stock springs can give me a measurement from the rubber bumper to its contact point on the cross member? I think it would help to have a measurement from the center of the sway bar to cross member as well. Any help will be much appreciated!!