Didn't I read, somewhere long ago, that an inexpensive and similar to the BTZS tubes ( I don't know about this, I've never used the tubes ) was the use a piece of PVC pipe cut to length and open on both ends. The film was inserted and rolled around in a tray of developer, stop, fix, etc. Since it is open, it had to be done in total darkness. Therefore, it is like tray development, but the film can't get scratched and it is easier to give individual sheets special attention, if need be.

It would work for all sizes of film and was very cheap. Does this ring any bells, anyone?

Closer to the topic, I use a 3000 series Jobo tank on a motor base. Works very well, but if I were just getting started I wouldn't recommend the expense.