Since I am not personally crazy about the blow-back from the mini-y comp, I called one of the experts close to me.  He said he would drill the mini-y through the end, but would prefer to take the front sight block off and do it right.  I asked him to just drill it thru from side to side.  He machined it out so that there are no angles blowing gasses back, and still left a little of the partition between the two holes.  It cut the blow-back by over 50%.   I'm really happy with it, and it looks REAL good.