1988 TT 7 | Andrew Stewart | Flickr

This is a link to my Flicker album of tubing companies' docs. There are a few unicrown type blades listed among the various brands. I see wall thicknesses range from 1.35 to1.2ish at the tops and some are thicker at the dropout end (likely a straight gage tube that was swaged down) and some less so (as in a single butted starting tube).

I started to scan and upload to my Flicker site bike industry catalogs I collected over the nearly 50 years of doing this stuff. I likely have about 50% more to go (when I build up motivation again, need to get really sick and have to stay at home doing "nothing") but there's a lot of interesting data for the looking here just the same. Andy.