No, and even the OP seems to have doubts about the copy stand so I would sort that out before upgrading any other part of the system, but then the tests that I suggested using Vlad’s Test Target would highlight such problems. For the sake of impartiality I’d love rto recommend an affordable alternative to the ‘VTT’ but I don’t think there is one.
Mark Segal’s articles can be found on Luminous Landscape now, you are of course encouraged by the site to subscribe but you can ‘do it later’. This one shows his rig. I think even Mark might agree that each of the components in this top of the range setup might be intimidatingly expensive for someone just starting out with camera ‘scanning’ though. Actually I think your own copy stand is excellent, and need not be expensive.
Excuse me for giving a link to your own setup but I think it’s more than relevant.