Finally got to the part that I was dreading. The B pillar had been hit at some point and whomever the piece of humanity who painted it before fixed everything with a gallon of bondo. The B pillar was a bit intimidating because, the replacement part came with the entire inner window structure and it isn't an exact match for a Biscayne.
After looking at it for a bit, we decided to go ahead and cut out the damaged portion and graft the new piece on the old one. I'm very happy with the quality of the replacement B pillar however, I can't say the same for the quarter panel patch.
The quarter panel patch is a POS. If anyone has to do one for an early Impala, Biscayne, etc., I would recommend going with an entire quarter (believe these are stamped better) and cut out the portions you need. The quarter came out OK, had to add in a piece of metal and some welding rod to fix the door gap and that is still a work in progress. I have a high spot on the back of the patch and a few low spots but, nothing that can't be fixed.
BTW, I'm getting very comfortable with stitch welding and plug welding