wildland01

What material is the non-lead/lead alternative wire made of? I have noticed many different "craft" wires in the stores and wondered if these could be used, any thoughts on that? I would think they could work, as long as the material was malleable enough to form around the hook and dense enough to add adequate weight...? Also, I am fairly new to tying and was wondering if there was a formula/rule of thumb for choosing the wire size. Thanks!