1) Try using #300-#400 meshI've got a Genesis style rta and I have steel #500 mesh but found the process of wicking a pain. Also don't quite like the metallic taste even after torching the mesh.
2) after rolling then torching, dip in got water, then torch and dip in hot water again
3) don't coil your wire too tight
4) torch your kanthal before coiling
5) try not to let the mesh touch the inner walls of the ctr neck
6) cut the mesh slightly below the threading of the top screw
So far those are the few tips I have to reduce the metallic taste