If I may chime in.. The 500 mesh and beyond is because when rolled with a very small middle hole wicks 3 times greater than the 325. The 400 improves rolled the same way but only a little.
Mesh should be boiled in a water and vinegar solution to clean off any oils and whatever on it.
The latest with the pryex is use about 10mm long tube with about 8 wraps of 28g or 30g and leave a little space between the tube and the attie. Do not insert the tube into the attie as vapor production is reduced..
While using mesh works, the best so far has been hemp.. You can get hemp rope at the Dollar tree 2mm x 10 yds for 1.25$. Don't forget to boil it and dry..
I tried some hemp and it does work very well.. At our local
vape meet we plan on doing a workshop on this..