I used hemp in our protanks for ages, it kicks the crap out of cotton for durability but is a hassle to prep or else you get that woodzy taste. With tweezers I had to remove the bunnies and off colored shards. I assumed the off colored shards were shredded stalk pieces and contributed to the woodzy taste, also removed the bunnies since I was already removing the shards. My hemp builds had no woodzy breakin taste at all....my wife would have been the first to tell me.

I didn't boil the hemp either since I began using hemp around the time when boiling everything was all-a-rage.
Been building coils over 3 years now and the novelty wore off a long time ago so its turned into "have to do" thing and a long term hobby but its still fun to twist this and clapton that. If I was a new builder I would skip over all other wicking material and straight to using rayon to wick with.
FWIW....As long as my merlin sits on a mech that doesn't quite sit flush ontop the 510, it doesn't seep but put it onto a atty stand or a floating pin hitter it begins to seep...weird. I have the merlin sitting on a old KTS+ with a solid pin and a gap with very little juice on the bottom of the atty. I can say that my merlin does hold vacuum pretty good since it can sit for a couple days then open up the top and have a large air bubble come out of the juice hole, inwhich could be apart of its seeping but I dunno. I'm assuming me putting a 2nd thicker oring into the AFC groove along with a thin one(removing the stock oring) has corralled the seeping to a point but I have to be conservative with the building of coils for the merlin since its atty life is going to be spent on top of a mech.