Vixen clamp to fit old finder shoe location

[Commanderfish]

Hi everyone,

 

Does ayone know of a Vixen dovetail clamp which has mounting holes which are the same as the mounting holes on a standard Skywatcher/Vixen finder shoe?  I'd like to switch my finder shoe for a vixen clamp, and I'd rather not drill new holes in my dob.  A vixen dovetail could then be used to better secure my ST80 as a finder on my 16" Dob - and it would also enable me to experiment with other vixen-mounted scopes co-axially mounted to the dob.

The existing shoe looks like this: https://www.firstlightoptics.com/finders/finder-mounting-shoe.html

The problem is that the Vixen dovetail clamps which I am seeing on line don't seem to have hole pattern measurements on them.  Some do seem quite similar though.  For instance, Would this one work?

http://www.rothervalleyoptics.co.uk/adm-vixen-style-dovetail-plate-adaptor.html