Definitely "doable" KA Koncepts and race set up well on NP masts of high carbon content. Don't over do the downhaul though as NP tip is slightly softer.
I have my np x9's on my koncepts with 2cm less than recommended downhaul. However, too much downhaul and the leech gets floppy but the luff tightens up, bit of a trade off but not worth trying to fix! (cos it works).
