B3b) The competitor must not make notes. Penalty: disqualification of the solve.
But could you bring like 30 or 40 objects with you and place them on the table to memorize the cube and then touch over them during the solve or is that "taking notes" too?
Haha, great idea

. But i would say, that's taking notes, too ^^.
Uh, this could actually be serious: Configuration of the cubes on a table.
It is imperative that no one move the cubes the solver places down after memo (so that (s)he can pick them up correctly), if we do not want any judge interaction (and I don't think we'll ever let the judge hand the competitor the cubes during the attempt, as that gives the judge a huge responsibility to keep the cubes in order and not to make a mistake).
However, that means you could encode a bit of info per cube just by relative position. Perhaps you place them in a row, and each cube is a little ahead of the previous if the cube has parity, and a little behind if it doesn't -this would give a gentle reminder during the attempt. Also, if some cubes are distinguishable by sticker/tile feel, you could theoretically rearrange them for a bit more data (just tap over a few, and maybe pick them up, as if you were trying to make sure you still remembered your memo).
It's also possible to stack them n specific ways. (Start with a cube, go up, right, or down, etc.)
Also, regulating how one may place down cubes could be difficult if people like thinking of counterarguments (which, of course, we always do.

). If at all, I don't think we could agree on anything fancier than, say, requiring adjacent rows of x cubes.