Unusual over unusual

Also known as invisible cue bids.  I think almost all experienced players play these in some form.  The idea is that cue bids show good values in a particular suit while direct bids in the suits show lesser values.  However, I don't think there is agreement on which cue bid shows which suit.  Over 1-2NT(=minors)- for example, some play 3 as the heart raise while others play 3 as the raise with 3 showing spades.  The theory of the latter is that more bidding room is need when no fit has been found.  Things are even more complicated when the opponents' suits are not touching: 1-2NT(+)- for example.  Here there's an advantage in using 3 to show diamonds because a 3 contract is possible (unless the cue bid forces higher).

U/U can also occur when we haven't bid a suit at all.  For example, some players use a 2NT opening to show a weak hand with both minors.  Many use that over a nebulous or strong 1.  I'm sure everyone would agree --> and --> in this simple case, but what if the 2NT bid shows clubs and hearts?  Or black suits?  Would everyone agree then?

I've tried putting together some rules on which cue bid shows which suit, trying to optimize which is which but still keeping the rules relatively simple.  Comments are welcome.

If we have not shown a real suit (will include 1 and/or 1 openings for some):if the cue bids are touching (including S-C), cheaper cue shows cheaper suit above the cue-bid pair; more expensive cue shows the remaining suit.

if cue bids are non-touching, each shows the suit next above it (-->).

If we have shown a real suit:if both cue bids force to the same level in the suit shown, more expensive cue bid shows that suit, and cheaper cue bid shows the fourth suit.

if the two cue bids force to different levels in the suit shown, cheaper cue bid shows that suit, and more expensive cue bid shows the fourth suit.