You can. If putting the wick into the tank, through the small hole, you may want to try something like several strands of viscose bamboo thread (Aunt Lydia's brand), as I find them easier to shove through the hole, and stay intact. Cotton butcher's string may work.
You can also just use loose cotton from a cotton ball, but you may be better off leaving that just into the hole, and tilt to re-wet it.
Regarding rebuilding the eVod/ProTank heads, I thought I'd put in a link to a written guide, with pictures. I like those better than videos.
http://www.e-cigarette-forum.com/forum/clearomizers/404174-evod-protank-head-rebuild.html
Also, I wonder if you were putting a top wick on the coil, often called a 'flavor wick'. I call those an insulator to keep the coil from shorting to the top cap. Have to make sure the positive end of the coil does not touch any of the surrounding metal, at all. It's not good if the negative end does, but that would only be a partial short-circuit.