Rated 5 out of 5 stars

want to [shift]+[mmb] click a link from non private tab and have it open a private tab... can u integrate wit tab mix plus and offer the option

This review is for a previous version of the add-on (0.1.7.1-signed). 

This is most easily to do from Tab Mix Plus (or other click-related extension) side...
Because I don't like to make all-in-one extension, but provide API for other extensions:
https://github.com/Infocatcher/Private_Tab#api-functions
So, please try to contact with Tab Mix Plus developers.