OPST Smooth is awesome!
I got this line 2 weeks ago, but only today did some real field test.
Small, but deep river. Water was dirty, recently power station released water from reservoir. I fished very colorful streamer and caught 3 rainbows.
This line is a gem. I also have OPST Commando as separate head, but this one allows strip fly to very short distance, without bumping in the guides. Definitely best dedicated streamer fly line for trout. Also, I used it for overhead cast on some occasions, slowing down motion.
I use glass rod with this line, Echo Glass 486-4 (4wt, 8'6") , it allows wide load tolerance. But I think 175 grain is a sweet spot for this rod.
Rigged with 7'5 S6 sink tip + 5-6' fluorocarbon