Hi have a few strands in the channels and never had a problem, not even at 40w using 50/50 juice
I have no problems with 50/50 juice. Matter of fact, when I do a build for 50/50 juice, I do run a few strands down the channels, otherwise, it will flood. Most of my juices are 70-80 vg though and I have issues with wicking when I put any wicking material down the vertical channels.