Fomapan R-100 is a really nice old world silver rich film, with deep blacks, clear highlights, crisp whites, and fun to use. However, unfortunately, there is a perforation pitch problem, small, however it is there when compared to KODAK standard films. The Double 8mm does tend to extend out and is noticeable after more than a dozen frames. In practice, it's nominal and the film is very usable of course. This pitch variation is also noticeable on their 16mm films, but due to the larger frame size and longer perf spacing compared to Double 8mm, it's less of an issue. The 35mm versions, made more for still film have different perf shapes, but from various others shooting it in cine cameras, their results seem workable. You'd have to do your own tests of course before committing this to a project.
And yes, I have mentioned the perforation issue to FOMA some years ago, and received a polite letter and email to the effect that the punch dyes are older and they can't afford to spend the amount it would cost to redo them just to fix this variation.
The film is also available in Double Super 8mm, as well as having been custom loaded into Super 8mm cartridges. Owing to the thicker film base support, sometimes there are transport issues, something to check first of course. Since most of the small DS8 and Double 8mm 25ft/7.5m loading cameras do not use a sprocket to drive the film rather a spring roller on feed and a rubber snubber prior to takeup, a wipe of the film gate and pressure plate with silicone, wax, or movie film cleaner with lubricant will help the film advance...IF there is a transport issue with this thicker film base material.
Lastly, owing the built in anti-halation remjet equivalent in a dye form, there is no issue of polished film pressure plate ghosting. This reversal film is unique in that this anti-halation dye is dissolved out during the bleach stage of the B&W Reversal process. Despite a few odd issues with this film, it is a pleasure to use and it also does very well being processed in Sepia Tone Reversal having nice rich deep browns and tinted highlights and rich blacks (owing to the silver rich density they appear black where no detail is present).
Plenty of those fine BOLEX H-8 cameras around. The non-reflex ones have an advantage of no light loss due to a prism, or dirty or cloudy prism, use the less costly D-mount lenses, do have reflex viewing lens unit options if needed, tend to be more robust due to lack of variable shutter issues, and they generally can be purchased far less than their reflex counterparts. Best ones to consider are those with the frame counter built in and with serial number sequence range after 100,400 which had a major change to the claw mechanism, known as the film registration claw. These tend to be steadier and the backwind claw is steady enough to film in reverse using the small hand crank if you want to. In my experience, as long as the cameras are well lubricated and cared for and work well, even very old ones will produce nice steady images. The later H-8s also had an 18fps speed setting between the 16fps and 24fps marked range on the knob. Those H series cameras run well enough to use as small film contact printers if need be! Also, the small B and D models are very nice to use as well.