http > https redirect adding a " / " at the end..

I assume the final / is in the original request URI [HTTP::uri]. You can prove this if you add a logging statement like this before the HTTP::redirect command: log local0. "Original URI: [HTTP::uri]"

Something like this shouldn't be breaking your site anyway, sounds like poor code.

If you really must remove the / you'll need to modify the URI before you do the redirect. Something like this should work;

set newuri [string trimright [HTTP::uri] "/"]

and modify your redirect like so;

HTTP::redirect "https://[getfield [HTTP::host] ":" 1]/myco/somesiteorother${newuri}"