You have got 100 feet to play around with. Try some 5/64th, 1/16th. Sometimes I'll go pretty small and use an 18 or 20 gauge needle. I saw a post on this forum awhile ago that had some examples of how many wraps of what sized coils yielded what resistance. Just go for it, and try a bunch of different ones. As long as you check it with a multimeter before slapping it on a power source you'll be just fine.
32 gauge will work just fine.