As I was playing around with my Dawes frame today, and was wondering about the tubing (Reynolds 531 DB?), I took a similar-sized Union frame from the attic that I thought I knew was hi-ten and weighed both. Sure enough, they were about 400 grams apart. With the steel headset on the Dawes and the Shimano 600 alloy headset on the Union, the difference is probably even bigger.
I had a 26.8 mm seat post in the Dawes, and just out of curiosity I stuck it in the Union. It fit perfectly. What's up with that? 26.8 is not supposed to fit a hi-ten frame, is it?