I now am the proud owner of an Ensign Cupid, a 1920's camera, a thin sheet metal light affair with guillotine shutter.
Shutter speed is typically rated at 1/30 sec/
I was thinking of making a wooden bed to secure camera, and use a monopod, to better my chances.
Inexperienced with monopods and this speed range, I wonder if this will be stable enough?
Berry Thornton in Edge of Darkness explains how he tested very sturdy tripod, light tripod and hand held. He did better with handheld than with a light monopod. At a 1/30 I would use a tripod or hand hold.
There can be no standard answer since much depends upon the ability of the photographer. Try shooting a roll at 1/30th, choosing a few subjects that have sharp delineation. If no sign of shake you’re home free.
I never had a problem with 1/30 second exposure using a box camera, but a monopod could help, except for having to drill a hole in the bottom of a perfectly good box camera so that a tripod or monopod screw could be used to attach them.
Those camera were designed to be used hand held. That said, they were also designed for the negatives to be contact printed, so the level of blur may be less acceptable to the modern eye.
As Don wrote, this camera was designed for handheld use. It does not have a tripod socket. As the manual says, “For ‘TIME’ exposures indoors or in a dull-light, the camera must be rested on some firm support.” (From the manual at https://cameramanuals.org/pdf_files/ensign_cupid_camera.pdf)
No worry about the tripod mount: for my box cameras I made and use a L-shaped wooden bed with 1/4-20 embedded nut and elastics.
I suspect the manual instructions were written when standard film speeds were a bit different?
Slower. ASA 25 was common prior to 1950 (though that same film would become ASA 50 after the ASA standard change of 1960). That's why simple cameras back then had slow shutters -- to allow daylight photos at f/11-f/16 aperture.
The answer IMO depends on what you want to do with the images. Those box cameras were, by my understanding, designed with contact printing in mind, not so much enlargement. They frequently have lenses with a lot of *ahem* character, and a bit of blur wouldn't be very noticeable.
If you want to enlarge, I think a monopod would help at 1/30. A tripod would probably be better though. My $0.02.