I don't know very much. But in thinking of your dilemma, I am wondering if you removed the kerfed linings form the 'too low side' and re-glued in taller linings that you can then sand down to match the side thickness of the treble side. Since you will be routing off the side for the binding/purfling you may be able to salvage it.

Good luck!

Did you pre-taper your sides like you would on a non-cutaway? If so, that could be your problem. On a Venetion with a domed back, the side gets narrower as you get to the horn but gets wider again as it goes into the cutaway. This can cause the lining to get sanded to a changing width but the sides aren't necessarily off, bass to treble. Did you measure?

On a venetion, I don't taper my cutaway side as much and I profile the the back before putting on lining to prevent that problem.

I'd leave the taper. Tell folks you planned it that way. At least it's tapered the right way!

Don't know that I'd even bother removing the linings on that side, as long as enough gluing surface area is left. But, then again, I'm no pro. Just my opinion. Based on the fact that my current OM wound up with a taper, too. Intentional, of course.....

The cutaway curls back toward the center of the body and then back towards the neck the profile is vastly different profile than a non cutaway side. The elevation of the rim at any given point perpendicular to the body centerline must be equal both sides of the centerline. because the cutaway reverses direction the standard side profile will not work and will cause you to either over sand the non cutaway side or cause a tilt in the dish depending on how you do the sanding process.

Right. Just to be clear, I only profiled the sides once the blocks were glued in, and I then profiled the sides in the sanding dish. I then glued in the linings. Up to that point the sides were money. The taper only occurred once I went to sand the linings down flush to the already profiled sides.