Are you familiar with the loading and exposing the 2 sides of the 16mm wide Double 8mm film in the camera? There is a cleaver way that was designed way back in the 1930s to prevent the user from double exposing the film.
The small 25 foot reels have different openings on each side of the reel. When you wind your bulk roll down, you have to have the film correctly orientated on the reel in order to load it into the camera properly. Wind it wrong, it won't work, simple as that.
The pic below is how the reels will sit in your camera when you load it. The gray reel is the raw film, the black reel is the take up. Look at the film feed spindle and the take up spindle, you'll see how the reel notches work to prevent wrong orientation of the reels.
The gray reel has a faint #1 stamped on it. That means the 1st side of the film is being loaded. You also see the 4 notches on the spindle hole. These 4 notches have to be up when in the camera. If you were to flip the reel over and try to load it on the feed side of the camera, it won't go. A safety step.
The take up reel has 3 notches up on the spindle hole when loaded in the correct position. I added a 2nd pic of a take up reel so you can see the 3 notches better. Usually the camera came with a reel printed like the one shown on the right below. That reel always stayed with the camera as you had wound the film back onto the reel that came with the unexposed film during the 2nd run.
3 notches up on the take up side.
When you've finished shooting the 1st side, you flip the reels over and run the 2nd side through. Then process it. Slit it in half. Splice the 2 pieces together and run it on your projector.
Again, the reel with the 4 notches up, as in the below pic, the film should be wound so it comes off the top of the reel on the right side, emulsion down, or in.
As suggested in posts above, I'm not 100% sure if these small CAMERA reels with the different set of notches will fit on the shaft of an 8mm editor, possibly they will. You'll have to try them. I was weened on shooting Double 8mm as a kid, but I didn't wind down bulk loads of film. I used to process 8mm B&W film however. I did have a Baia film slitter. The 2nd pic shows film with Super 8 sprocket holes.
If loading the camera as I explained above doesn't quit make sense, I have an instruction manual that explains the steps. I'll have to scan it 1st, so let me know.
(it really is very simple)