wibowyer, even with a 50-55# bow it will go thru a deer. The sharper the better. The fact you have the tang so far up the shaft is the major good point. As far as folding it---no way. If the tang is seated against the bottom of the grove, it is as solid as you can get it. No you do not have to tapper the shaft any more than you already have. Good job.
Dick