lastchance,
When nymphing I use two different sizes of tippet:
I start with a 3X Rio Trout tapered mono leader. Then I tie on a length of 4X Rio Fluoroflex Plus tippet and attach the first nymph. Then I tie on a shorter length of 5X Fluoroflex Plus Tippet for the dropper nymph. If I need to use split shot (we do on many western rivers) then the split shot goes on the mono leader just above the knot to the fluorocarbon tippet.
Larry :D ---sagefisher---