My understanding is that "balancing" a rod and reel has more to with the physical weight of the reel than it's line rating. Since weights vary between makers and models of reels I am more interested making sure that the feel of the rod and reel combo is comfortable to me than whether or not the line weight ratings are matched. Other factors go into reel selection as well, for instance the type of fishing and the target species. Some species (steelhead, salmon, bones, etc) require a better drag and more backing capacity so I look for those features.

Of course, I'm no expert, but that's my understanding. I'll be interested to see what the gurus around here think.

Rick