If it ends up being a 6wt but you want it to be a 5wt, buy a 5wt Rio Grand...
Just wondering, what length is the rod and do know the model?
All of the rods I use on small streams are shorter (from 5"0" to 7'0"). If I am fishing a rod longer than 7'0" I am fishing what I consider a medium sized stream. That being said, with the exception of four rods in the short rod quiver that happen to be 4wts, all the rest are 3wts and fiberglass and very light because they are shorter.
Because they are shorter & lighter to achieve the static balance I prefer with the reels I prefer, I need a smaller reel. A smaller reel holds a full length DT 3wt line with no problem. A heavier line requires a bigger reel or needs to be cut in half.
That being said I have NEVER felt the need for a heaver line in any tight quartered place I fish. If there is a rhododendron tunnel or some other obstruction, I just shorten and modify the arc of my casting stroke which tightens the size of my loop and I pop my cast in to the opening... I should mention that NONE of my rods are fast so high line speed ISN'T what is closing up my loop.
Excluding the bamboo rods, I only use Sci Angler Mastery DT lines. The Mastery DT has a very short front taper. If you fish a short front taper line AND a short leader on a moderate action rod you will have more of the line belly out past the tip top with less overall line/leader length so short casts are a breeze. For that reason I never felt a need to over-line even when making 10 foot casts.
Try the same short cast with a fast rod or a long front taper line and a long leader and you WILL feel underlined.
Good luck dialing in the South Bend and have fun fishing!!!