Hi Sam, How are you? I have been successfully grinding taper lams , thanks to you after watching your youtube video.
I have tried two types of string, cotton and nylon string. Cotton will prevent sliding a bit(but dont think that is bit) but they arent as strong as the nylon (same size) u should do a dry run and you will find that sliding is not much a problem.
Wedges, the sharp end need to be paper thin, like your riser fade out. This will help when u try to slide the wedge under the string...... sand down the belly of the boo wedges NOT the rind end.....
Sam, send you a PM/mail , please check......
MoeM....boo belly? have tried that, but when you have a boo belly, pre-tapering the lams must be very precise, or then you will have to remove materials from the boo belly. I find it very hard to change the tiller if i have a "hard " spot...