Sorry for the late reply, but I just wanted to say I use a wire keeper in my poison tail mold with no ill effects. The main reason I use an additional keeper on the this is so I can have one notch for the skirt, one for a set of mouse ear rattles, and the wire to hold my plastic. Having the rubber bands recessed in the lead keeps them from easily getting cut by the pike I deal with - if they don't rob me outright - when I'm chasing the greenies.
Note: this is not the Do-it wire keeper, rather it is a 1.5" piece of 22ga wire that I lay behind the hook when molding, and I kink it after everything else is done. (I removed the slightest bit of material from the mold just behind the hook, and when I don't use the keeper wire, there is no lead leakage because the gap is so small.)