I have a noticeably harder time with triplet feel than 16ths or other 4 note groupings, unless it’s sextuplets a la Petrucci or the Gilbert thing. I just don’t play triplets that much.
I would recommend doing small bursts of 5 notes (if doing 16th note feel) with different variations on where you change strings, that way you get a solid start and end on a beat (downpick to downpick). Up it to 7 notes if sextuplets / triplets.
I agree that should always be the goal, but in my experience, it will never catch it due to the loss of speed when changing strings. Still, I have benchmarks I try to aim for that are different percentages of my max trem speed (1nps crosspicking, 2nps, 3+nps, downpick single note, downpick 2 note chords).
You might have to go back to the drawing board with your picking mechanic, IMO you can’t squeeze out more speed once you’re “going fast” unless you change something fundamental (picking motion, secondary motions, picking depth, attack, etc).
I think 180 sounds fast in context, but it all depends on your goals.