I will at times tilt my brace and bit to further enhance the draw, mostly when I have guessed on the shy side of my 1/8", so I am compensating. I don't prefit and redrill. I use my combo square as a guide to help until I'm into the further side of the mortice than let it go, checking the start and than the realignment in the mortice. I bore them horizontally not from the top as well. My shaved pegs have a fair bit of taper, I peek in the hole at raising and select an appropriate peg. Tim