Have you tried to mount the flat objects on it’s edge, so that you can scan both sides in one turntable revolution? Doing this as well as adding april tags onto the turntable itself, should give RC more than enough information to align the images properly. Of course it is still possible, that the object might be too thin and produce holes when reconstructing the mesh, but maybe worth a try.
kinda like this:
This will obviously only work on objects of a certain stiffness, otherwise you won’t be able to mount them standing on their edge without folding over.
Cheers
Guillaume