First!
Get the subsite_url with the site node procedure! Don't read the nsv directly.
Second build URLs with export_vars then you don't have to play around, removing the trailing slash etc.
Third, I believe you are referring to the bulk actions links at the bottom of the page. If you are, that are not appropriate for a single link. They are for taking actions on multiple items. The bulk actions take their parameters from the key specififed in the list, plus any filters you may have applied.
