12 string fanatic here, at one point had 6 electric 12s (and two acoustics). I really like the PRS 12 string set (.010 - .046), good prices through Elderly.com. Needless to say, I buy by the box, call them to inquire prices, they're helpful people. Strings sound great and last well, who likes to change strings on a 12? On a couple vintage axes, I have used SIT 9-46, not that much lighter but different weight ratios.