Are you trying to adapt some stereoscope? I do not recommend it: I did it some time ago and the stereo view was deformed and uncomfortable... I spent many days working this way and finally gave up. Later I purchased a true stereoscpic diplay based on dual monitors and a splitting mirror... and OMG, this is glory! I love it. I'm an absolute fan of stereo plotting it feels like diving into the reality. Seriously, forget split view. Aspect ratio gets wrong, Agisoft has done something wrong with the split view and I have already told them but they don't seem to care enough about old school stereo photogrammetrists. Get a stereo ready card and just let me know if you want a proper stereo display.
Cheers