...while some people recommend stepping up a level for dry lines in order to load the rod better, I'd recommend you stick to a 5 wt. in the sinking line--they're quite heavy as it is and the extra weight would only overweight your rod. I used to use a 6-wt dry line on my 5-wt, but that was when I was using a cheap line...most modern lines are pretty well balanced for the rods they're rated for.

Welcome to the board.