Mike,
Those racks were custom-built for each frame. Things like tire clearance (and thus distance from fork crown to canti bosses, etc.), head angle and so on vary from bike to bike.
So a used one won't fit right. They should of course be horizontal, and since there are no adjustments... The only way to do it right is to take the bike (plus photos of a similar rack) to a "constructeur" who makes racks, and have one made. Try Mariposa in Canada (they'll need the fork, better the entire frame) or Alex Singer in Paris. Rando-Cycles can do it, too, but they use thicker tubes...
>I am in need of a front rack for a Rene Herse that mounts on the Canti
>bosses.
>
>Mike Tatum
>San Diego
--
Jan Heine, Seattle
Editor/Publisher
Vintage Bicycle Quarterly
http://www.mindspring.com/