Beginner question.

Hello,
Have been reading the forum for some time now and am really grateful
for all the information that is shared, it has answered alot of
questions I had. I live near the Rocky River in Northeast Ohio. Right
now there are steelhead in the river and it has caused people fishing
down there to act as aggressive as the fish they are after. So I fish
it in the Spring through early Fall and target smallmouth and
bluegills. The smallmouth are in the 10"-16" range and put up a good
fight.. I'm looking to buy a new rod and am trying to decide between a
5 or a 6 wt is there a considerable difference?. I'm rather new to fly
fishing, have been spin fishing for about 25yrs. After I got over the
intimidation factor of it and became passable with my casting I
realized what an enjoyable experience it can be.
Rocky river is a small-medium sized river and is a Lake Erie tributary.
Right now I have a fiberglass 8' rod and it feels like a tree trunk
with a spaghetti complex...plus I have a bit of cabin fever and feel
the need to buy something so I can look at it in the basement for a
month or two and use my imagination. But I've heard ranges all over the
wt scale for smallmouth and was just wondering what some have used wt.
and length wise.
Thanks,
Janus