Thanks Riley.
Gary, I built it with a BNC-70K from BMS, described as "long ogive with blunt tip". It's not quite the right length/shape for upscaling the PNC-50Y, but it was the closest I've found. It's 7" long, but the rounded tip truncates what would be a longer ogive shape otherwise. I've done several designs with BT70 that I haven't gotten to yet. FWIW, Apogee has a 5:1 (IIRC) ogive cone that fits BT70, and is made to also be trimmed into a boat tail. I think its about 10.5" long. The cone was too long and raked to look right on the model, so I wound up with the 7" shorter ogive shape and extended the BT to make up the difference.