Goat Hill Photo is great for slit film; I haven't tried their splitters. You can use 16mm movie film. Also microfilm; here's an approach I got from a Subclub user some time ago. It's for Agfa Copex microfilm at ISO 50, but best to avoid high contrast situations:
Mix a Sodium Sulfite solution of 2 oz Sodium Sulfite to 1 liter of water. Mix 2.5mm of HC-110 (concentrate, not stock solution) to 200ml of Sodium Sulfite solution. Develop for 6 min at 68 degrees F with agitation every 30 seconds.
What about 16mm BW Cine? Will that work? I have a 16QT I'd be interested to try (assuming i can find a Patterson reel for it)
Yes, you can indeed use 16mm movie film. I bought Eastman 7222, 100 ft. 16mm single perf, Double-X negative film direct from Kodak for about $35 shipped. You should be able to spool at least 60 rolls of 18 exposure each from that length.
I taped a length of twine with a large knot at 18 inchs to the plastic carton that holds the film.
IN TOTAL DARKNESS!! I spool out about 19 inchs, close the lid tight, and snip off the film leaving 1/2 inch sticking out from the carton. Then I insert the end of the film in my spooling stick, a 5/16 wooden dowel, 6in. long, with a 3/4in. long slit in one end made with an X-Acto razor saw. Spinning the dowel, I guide the film using my finger and thumb along the edge of the film to a tight roll. Emulsion side in, with the perforations next to the cartridge bridge. Then pull the roll off the dowel, keeping it tight, and insert into the feed (small) end of the cartridge, leaving about 1 in. sticking out through the light trap. Now put on the cover and you can turn on the lights and complete the loading. Tape the cover on the feed side with blue masking tape, blue masking tape can be removed later without leaving a residue. Pull out another inch of film from the feed side and tape it to the take up spool, insert the take up spool in the large end of the cartridge, tape on the cap and you are done.
If you can't find a reel for your Patterson that will adjust down to 16mm then you can buy a Yankee Clipper II tank and reel from B&H Photo for $16.99 with free shipping. This is a cheap tank and reel, and I mean cheap, but it is workable and the reel will adjust for 16mm/110 size film.
I develop Double-X with HC-110, dilution H, 1:63, as a one shot for 11 min. at 68~70 F agt. 5 sec. every 2 min. water stop, normal fix, rinse, photo-flo and hang to dry. I don't bother trying to find 16mm clear neg files, I just put them in 35mm clear neg pages and they seem to stay put fine in the binder.
Addendum to last post;
Kodak has (still has I hope) a 1-800 number to order movie film directly from them but for the life of me I can't seem to locate it in my paperwork. If you roam around their website you might find it. I'll keep looking and reply with the phone number if I can find it.
Another thought. (been thinking too much lately)
New 110 film, both color and B&W are now becoming available from sources like Four Corners Dark, for about $8 a roll. The film is made in China, brand name Fukkatsu, (the name apparently meaning rebirth or resurrection in Japanese).
I wonder if the factory making this film would see a market for Minolta style cartridges? There are still a large number of Minolta 16mm cameras that work fine. The simple 16II is very reliable as well as the P and Ps models. The trouble of course, is finding and contacting the right people. I would have no idea where to even start but somewhere, someone must know.