My first real "lightweight" was a Viscount, sub 20 pounds back
in late 70's early 80's.
The bike was a marvel, and a pain in the butt due to all of the
nonstandard stuff that Lambert put on it (the bottom bracket
stands out the most). I commuted daily on the death fork, and
well, never had a problem. I did get a nice chrome replacement
from Yamaha who bought the marque.
I'm kind of looking for a 21 inch aerospace pro, just cause
I liked it and well, the whole nostalgia thing.
I wouldn't pay much more than 100 bucks for one tho, very
little collector value in it.

Marty