Working with 8mm and S8mm film

I have captured footage on 8mm and S8mm film frame by frame to a PC using a telecine type arrangement with a WorkPrinter XP (modified projector, mirror and lens, and modified synch mouse) and video camera. The 1950 vintage 8mm film camera captured at 8 fps. The 1970 vintage S8mm camera captured at 16fps.

In importing the video clips to mocha, how should I set the Frame Properties for Frame rate and Pixel Aspect Ratio?

You should set the frame rate at whatever syncs with your sound, but if it is an image sequence it effectively doesn’t matter, as image sequences are one to one. But you want the pixel aspect ratio at 1, or square pixels, most likely. It will all depend on the final composite you are making. If you are working in a compositing or editing program, make sure mocha’s settings match what you’re using in your target software exactly.