Hey Grady, I'm not sure what size buck tails you are throwing but being you posted in saltwater I'm going to assume that they are pretty large. I like using Crazy angler tackle for my thread as I use Danville flat waxed nylon in 210 denier 99% of the time. If you are tying large buck tails like I mentioned, say over 1oz, then perhaps you might want to look at gel spun thread, it is abbreviated as GSP and comes in 280 denier, that will be very good for salt water bucktails but 210 denier will also work.