I use Berkley "Big Game" mono in Fluorescent Chartreuse for my leader butts in either 40# or 30#. Helps me to see takes and gage distance. My terminal tippet is clear mono or fluorocarbon depending on wet/dry application. I think the biggest issue if fishing upstream presentations is to NOT line over catchable fish in their feeding lanes, and get a natural presentation. When this becomes near to impossible, scout out your approach and 'feed' line and leader downstream to deliver the fly. I think a nice soft delivery and a good drag-free drift trumps color any day! The leader material and construction should be such that it instills confidence for the fisherman to consistently achieve good drifts/presentation.