Seaguar is a good brand. I would think any of the name brand fluorocarbon would do the trick. I, unfortunately, do not pay attention to the line diameter. I have spools of various fluorocarbon in 2, 4, 6, 8, 10 lb test that I use for cold water fly fishing and spools from 12 to 40 lb fluorocarbon that I use for warm water and salt water fly fishing. A 200 or 400 yard spool will last you a long time. I concur with using mono for dries. I'm not even sure they mono tippet material anymore. You can do the same thing, pick up a spool of mono 2 or 4 lb test for your dry fly fishing.