I've got my own list that I try to keep updateed with each week's moves - in this I try to rate them as follows:
0 - easy to lead
; lady can be given no doubt as to where they sould be/go
1 - standard
; if lady picks up an offered hand or follows smaller leads then the move is easaly led
2 - difficult
; move requires a known sigal or the lady to have knowledge as to what is expected of her (dips, leans...)
3 - impossable
; requires all of the above, and verbal instructions (normally airials)
Most moves I rate as category 1, but things like the pretzels and tunnels I give a 1.5 due to the ease of tying each other in knots. :sorry