Thanks for posting this, I have never heard about trimming/thinning the tails. I will have to give this method a try next time.
Can't take credit, it's something I pickup up from @JeremyR over in the rayon thread. He's probably the biggest contributor to wicking with rayon worldwide. A rayon demigod for sure.
Just so happens that wicktail trimming works with cotton too especially when trying to get that perfect amount of wicking density inside the juice channels of high powered attys (50w and up). A little too much in the channels and it's dryhit city once vacuum is formed in the tank, not enough in the channels and no vacuum is formed causing the tanks to leak when tipped on their side.
I've gotta crack the code for every new tank but once I have it, I have it. The only problem I'm having these days is remembering how I wicked 20 different tanks.