Dave, try this out. Get all 4 Beatles cut out again, and then take scissors and cut each image out on its own, with 1/2" or so extra vinyl at the edges. Apply all 4 in the exact spot on the disc where you want it to be, and get it all smooth with no air bubbles. This will be easy since the vinyl pieces are only 2"x2" or so instead of one 10" square piece.
Then, cover each Beatle with some transfer tape (just enough to keep their vinyl from getting goobered), four separate pieces just bigger than the images. Cover the whole thing with an uncut piece of vinyl, put a new blade on your xacto, and lightly trace the images out of the covering vinyl so as to remove only that piece and not cut all the way down to the disc.
Basically, apply the four images separately (makes it really easy to do so without bleeds) and them mask the whole disc appropriately. If you do it carefully it will be a surefire no-bleed situation.
Keep it up, mang!
We are not like those other golfers. We throw our clubs and keep our balls where they belong. -Ol' Bob