Maybe a bit ghetto but what about bending the V out a little. It won't take much to move the spread 1 degree.
Think of it this way: if you brazed the seat tube into the BB shell and then measured straightness and noticed the tube was angled down 9mm towards the end of the tube, a simple cold set will bring the tube up and into alignment.
Last edited by Nessism; 02-18-19 at 09:55 AM.