Sounds like your doing O.K. with the rod applications ~

Rod action, as I understand it anyway, is that there's slow, medium and fast action. It has to do with where the rod bends under a load and how it recovers from a bend. According to my fly rod reference, fast action (30% of rod bends) cast further and do a better job with the heavier fly. Slow action (90% of the rod bends) do a better job (at least for me) of gently laying down a dry fly down on the water surface. A medium action rod (60% bends) and is a compromise between the other two. Then you have line weight, which I most generally follow the rod manufacturer's designation for the rod and sounds like you are, too.