The link Tomcatt posted has some really good info in it.. As Emonty said it may be off QC ie: Crap.. but the info is free to read and understand.. Mainly because some of if not all of the Ebay mesh is probably coming from Alibaba.
Note the description of Twill..
Stainless Steel Filter Wire Mesh Twill weave:
A square pattern weave where each weft wire passes over and under two warp wires and each warp wire passes over and under two weft wires.
The description of Plain..along with where it is used..
Stainless Steel Wire Mesh Plain weave: for Printing
A square pattern weave where wires are equally spaced. Each weft wire passes over and under one warp wire and each warp wire passes over and under one weft wire
The result is that the Twill according to the listed specs have about 50.1 open area.. and that is the 400x400, 500x500 and the 635x635..
The plain weave according to the specs for 400x400 have about .40 open area at .023mm wire gauge which is about what we get from the mesh company..
Their 500x500 is made with .018mm wire gauge with an open area of 41.7 ..
While what is coming from The Mesh company is 500x500 at .023mm wire gauge with an open area of 26..
If I have been following this thread correctly the smaller the open area the better wicking..
With all that said, has anyone checked what the Co-op is supplying according to weave, wire size and open area..
I got all this for Free from that site..
Hope it makes sense...