80 or 100 lb test for my 12/0

i would put 80 on one and 100 on the other or 100 on both

If you want to target the larger sharks you need to maximize line capacity and maximize strength,,,,,,,,80 or 100 lb test wears out(frays up) too fast especially if you fish every week and gets cut too easily in Florida style fishing with so many reefs,sea fans,lobster and crab trap bouy ropes so I would go with 130 braid on the bottom (to maximize yardage) and 130 mono on top to have the stopping power/abrasion resistance .With the invention of thin braid lines you can pack on much needed yardage on the bottom that you won't need til you hook that massive beast.A large percentage of large sharks are hooked with a short drop usually just outside the surfline so this leaves quite a bit of line on your 12/0 but if you like dropping your bait out far the braid on the bottom becomes even more important when you hook a large shark that is quickly making line disappear off your spool.

Just as important is to have a plan in place for the day you start getting spooled and #1 is to have backup reel ready when you anticipate you will be losing all your line.Make two or three loops at the bottom of your line so that when you are getting stripped and the loops start coming out you can slip a snap swivel in one of them . loop in your

I agree with Will. I think i would put the 250lb braid because after a while everything weakens and the 250 would last longer. saw some on amazon for 89$ 500 yds. Power pro green.