I will also join the band wagon advising you to get one of the classic stereo cameras. These days, it is alot of work to cut, align and do the work the lab used to do. I do not know of any lab that will mount your stereo slides. Since I only have the classic stereo Realist hand held viewer, I can only tell you the results will make you giggle every time you look at your work.
What makes it more rewarding is that I use my dad's stereo realist camera he bought in the late '50s.