suzanneb: jack keller's site as always, every thing you always wanted to know about sulfite and sorbate but were afraid to ask
i'm a bit late to the party but i also agree with taticalhooligan way above, adding the cherry juice to back-sweeten. i did this once and it came out pretty good, way better than when i racked onto fresh cherries.
as for clearing, unless you have a pectin haze it will clear. if you're just using bottled or concentrate juice, you won't have a pectin haze, so it will clear. that super-kleer / turboklaar stuff works an absolute treat in skeeter pee, never tried it in cider. i don't know if it strips out any flavor? if you can get it into a fridge you can try a few days of cold crashing, should help knock the yeast out of suspension