I fish smallish water, so I use a TFO BVK 10 wt. If I was fishing bigger water more often I would (and will eventually) use a 12 wt. But guys I fish with who do use a 12 are over gunned in some places, their flies land on the bank, in trees, tons of slack at the end of a cast & they wonder why, lol. I do not have the long extended butt, they do look effective.
I'd rather have multiple lines than rods, I keep 3 spools.
80% of the time - SA Titan sonar sink line
15% of the time - Intermediate line (including topwater)
5% of the time - Floating line
I use 24" 40 lb mono looped to 12-18" 30 lb bite wire to rio quick snap.