ok first off i think thats a great question scotu and i would try to answer it for u if i had a copy of smash right now but i dont, so im gonna wait for the answer whenever u get it.
another question: I havent experimented with it much, but i found a tactic which may lend itself useful to multishining, with little plractice i could do it at about half of the time. some peopl have rediculous ways of multishining like using 2 fingers or even slaming the control stick up and down, but ive been just kind of sliding my thumb directly from Y-> B while im holding down on the control stick, but im not just doing it to multishine, im trying to do it EVERY time i shine, and i think if i could get the technique down, i could to a shine out of: another shine, a dash, or shield whenver i want and although multishining this way is slow (harder to hit Y and reshine a second time after doing it once) i think its much easier than repositioning ur hand.