Adding thickness just doesn't look right. The green underwear he first had is a good example of unnaturally thick cloth. I now duplicate a portion of the body mesh I wish to clothe, then extrude the sleeves or legs etc. and push pull vertices until the shirt or pants cover the body. Your right about the complications that occure when you try to adjust a mesh that has thickness. The jacket on my Elfette character is different in that it is box modeled. Here's the jacket with Elfette: