I also like a red and blue fly in clear, cold water. (see the Cop's Lights thread for the red and blue spey I have been using for several years.) Another variation of this fly I would tie and use is green and blue done by simply using fl. green wherever you have used red. Also, a fl. yellow and green (use fl. yellow instead of red and green instead of blue) or fl. yellow (instead of red) and blue are effective in glacial water.
Keep using the colored threads instead of colored cement (unless you use black cement to finish the head on a full-dressed featherwing) because it provides a more subtle finish to the fly. And there are far more colors available in thread than in colored cement as well.
Does Bogie lay at your feet when you tie, or does she like to get into your materials?
This is also a lovely fly that looks like it would be a winner in the low water of late summer and early fall.