Looking forward to seeing how the install and fitting works. If you run into a stumbling block, post some pictures and let us know what's going on. We'll gladly offer to help noodle something out.
EDIT: Looks like I was 2 finger typing away while you had some pictures loaded and coming - hahaha! My timing was a bit off.
I can see what you're working with and think your plan stated looks like it will succeed IMHO. Only suggestion I might add on what I see is perhaps you should add some nuts on the threaded studs. First add some to the studs to cinch them tight to the collar. Then once you establish where your side mount plates need to be, add another set of nuts to the studs before putting the brackets on them, to stop the collar from moving side to side and maintain the width spacing of the mount brackets. The final set of nuts would go on the opposite side of the brackets to secure the brackets to the studs with the backing nuts to stabilize the brackets and column clamp.
Clear as mud???
