My memory is really bad. First, I forgot about the frame alignment tool above when checking out the Bianchi. I did use Doug Fattic approach using a 4' level and digital calipers to measure.
1971 Bianchi build
if you don't look, I was able to realign the rear triangle to a point of having only .5 mm difference between the measurements compared to the 2.+ initial difference. No frame builder used, sorry. Yes I also built DIY DO alignment tool and checked it out.
When appropriate this winter, I will come back to this issue on this frameset.