sorry for the delayed reply.
after the coathanger trick I've used the oil method, galvanizing, and have used an interior sealer kit (caswell - which is reported to be the best <and they warranty that>).
my galvanized tank worked well, though it took a while. I used a large/long pencil zinc as an anode but with reverse polarity to that of the coathanger anode (used before in luring the rust off of the tank wall). this reversed the process, putting zinc on the wall instead.
the caswell lining process was simple, very effective and FAST. if you want this resolved overnight get a caswell kit. it works fine after tossing in some nuts and bolts, acetone, and shaking a few times. it actually works better when the tank is rusty inside still (so they say, but I cannot disprove that).
best of luck!