Shane –
What rod are you throwing? A lot of newer casters, particularly bigger men with athletic backgrounds, find that they get the most out of a stiff, fast rod with a fairly light line on it; both the stiffness of the rod and the lighter line ensure that the rod doesn’t bend too deeply. For casters with a tendency to apply just a little too much power at times, this can be advantageous because the rod absorbs some of the excess energy the caster puts into the stroke.
That doesn’t mean you’re wrong to want a line within the rod’s true rated grain weight window, by any means. Typically, most companies’ lines which are labeled “trout” or “selective” are going to be in the right window. My recommendation would be for Scientific Anglers’ Mastery Trout or Orvis’ Wonderline Trout, both of which have similar profiles. Rio makes the Rio Classic Trout, while Cortland’s 444 Lazerline is an old favorite of many anglers.
These lines are sort of like .30-06 cartridges or 50mm camera lenses: they were the sweet spot of the lineup and received the most development for the longest time; thus they are all just about equally good at being a general purpose line. When you get into the “selective” series, you’re getting a line with a longer front taper meant to turn over a dry fly softly. These can be just a bit harder for a new caster to unroll properly, and also have a tendency to crash with heavier flies (like streamers or weighted nymphs). But they are usually right on the grain window or even a bit light.
Best,
Zach