I'm probably going to buy an older G-1 (pre-1965) in the next couple of days, and one thing has struck me as I've been hunting: measurements seem to bear only a slim relationship to the size as per labels. Is the fit of the G-1 problematic or is it OK to buy an old one based on the measurements of something one already owns? What I mean: I have a tweed jacket that measures just under 19 inches from shoulder to shoulder and about 22" across the chest. I would guess that to be around a 42, but I've seen G-1s with similar dimensions labelled 40s or even 38s. What gives? Are there structural peculiarities I need to know about, or should I just take the plunge and go by the measurements, not the label? Obviously different contracts were cut differently etc etc (I've been giving myself a crash course over the last couple of days) but if the more experienced could tell me what to look out for, I'd be most grateful. PS: This is a pretty basic question and other threads touch on it, so mods: please feel free to merge it if that's less annoying for everyone else.