I have a certain experience now with E-6, which I practice since last October, thanks also to the precious help of this site. I want to begin processing C-41 as well, and have ordered the Rollei / Compard Digibase C-41 5-litre kit.
With E-6, I use a Jobo CPP-2 with lift. I use mostly a Jobo 1510 tank (1 roll at a time) prepare chemistry one-shot, use the same chemicals for 2 processes, then discard all the 6 baths (that would mean 2 films with 140 ml final solution). When I use the Jobo 1520 (2 135/36) I would prepare 240ml, use twice (4 135/36 in total), then discard all the 6 baths. At the moment I only reuse the stabiliser.
I have some questions regarding the Digibase C-41 kit.
1) Declared capacity is different for colour developer and the other baths. Using a Jobo 1510, the instruction sheet says the capacity is 2 - 3 films for the colour developer, 3 - 4 films for bleach and fix, and 8 film for the stabilizer. When using one-shot chemistry, suppose I want to use colour developer 2 times and bleach and fix 3 times, I should:
Prepare 140 ml of each bath;
Make two processes, then discard only the film developer and prepare new one;
Make one process, then discard bleach and fix;
Make one process, then discard developer and prepare a new one;
Revert to line 1.
That's impractical. I am going to process E-6 also and don't want to keep too much accounting regarding what is what and how exhausted it is. I would like to prepare baths, use them within one or two days, then discard everything but the stabiliser.
So the first question is: 3 processes with Colour developer give real quality, or are there any risk with quality, considering that I will be using a rotative processor, which means a lot of swirling and mixing with air during treatment, i.e. a lot of oxidation? The degree of quality that I aim to is the one obtainable by using E-6 one-shot chemistry only twice and then discard. I see no difference at all between the first process and the second one.
That would allow me to prepare all the baths, use them 3 times possibly within 24 hours or so, and discard all of them, using the colour developer at its "maximum" advised capacity and bleach and fix at their "minimum" capacity. I would process either 3 rolls (1510) or 6 rolls (1520) making three processes with each chemistry dilution and then start again with newly-mixed chemicals.
1 bis) As an alternative, could I dilute the bleach and fix more than per instruction sheet, so that I use them only twice, and proceed as I do with slides, i.e. "two-shots" and then discard chemistry? How much should I dilute bleach and fix?
2) In what does a stabiliser for C-41 differ from a stabiliser for E-6? Can I indifferently use my E-6 stabilizer (stabiliser proper, it contains formalin and hardener) with C-41, and Rollei stabiliser (contains 1,2 benzoisothiazolin-3-on, whatever that means, and does not contain formalin) or should I keep two containers for the two different treatments?