I have this rod and have used OPST Commando, Rio
Scandi Short, Rio
Trout Spey, and various 5wt thru 7wt DT lines.
I agree with all of the opinions expressed in this thread, but listen to Blix and choose your priority, and line the rod accordingly.
I don't nymph, so you're on your own there, but maybe this will help anyway.
OPST 250, easiest to cast, will do your heavy hauling.
Trout Spey 265, almost as easy to cast as OPST, very versatile. It can tow some weight (Rio Trout Versileaders with dries to moderate streamers), but turns over nicer than a skagit. The shooting line is very thin and mends only slightly better than mono.
Scandi Short 240, slightly less easy to cast than Rio
Trout Spey. Tows a pair of soft hackles or a light streamer on mono leaders. Way more delicate than the other shooting heads. When looped to an up-sized (heavier than recommended for a given head weight) Rio
Connect Core shooting line, it still does some distance, but mends pretty well for swinging.
As for DT lines, least easy to cast, useful for skinny water and small flies (dries, wets, and really really light streamers) if you dont have to shoot line. You do have to use different technique than when casting shooting heads. There is almost no rod feel with a DT. Best match for me so far is a 6wt SA Mastery DT.
Hope this helps