I think I have it now...

Since I found Dignan's 2.bath C-41 developing method I am using it but always trying to improve it in order to get better results. Well, my last but maybe not the ultimate and superb adjustment to the method lead to the following recipe for the 2 baths:

Bath A:

1 g/l Potassium Metabisulfite
9 g/l Sodium Sulfite
11 g/l CD4

Bath B:

25 g/l Potassium Carbonate
0,6 g/l Potassium Bromide

Bath A should be kept  in a dark bottle with little air volume. If it gets pink it is oxidized and will work very slow, it should be discarded then. But if kept in a dark bottle with little air volume it will last for months. This first bath is to be used as first and because of this it will decrease with time, some 10 ml each time. If you need 500 ml of it to fill the tank for 120 films, you should prepare 1000 ml and use it until you reach your minimum. And if the bath is still good (no color), prepare more 500 ml and mix with the remaining and so on.

Bath B is, IMMO, the key for good results. Trial and error showed me that 53 g/l of Carbonate is too much and will give green negatives, magenta positives, and you have to tweak a lot in software. A slight increase in Potassium Bromide from 0,5 to 0,6 g/l and a reduction of Carbonate to the half, from 53 to 25 g/l, gave me the best results. Even so, too much or too less agitation may produce spots and drag marks. Frequent and soft agitation is needed. I am using now 5 gentle rotations with the axe of the tank inclined each minute, after the first 30 seconds of constant agitation.

Generally I develop my C-41 films as follows:

Bath A - 10 minutes or more at room temperature
Bath B - 10 minutes or more at room temperature
Wash - I wash for several minutes, maybe 10 minutes too
Fix - I fix for 5 minutes with rapid fixer, the same I use for B&W
Bleach - until the base is clear and double the time.
Rinse 3 times
Refix for other 5 minutes
Wash very well for 30 minutes
Hang to dry

Normally I use Blix instead of the 3 steps bleach, rinse and refix.

After the first Fix you may open the tank and follow the process at light. This is the reason why I fix first, Exhausted Blix or not properly aerated may produce surge marks and it is annoying to rebleach and refix and wash and wait for drying.

Do not hesitate to ask me for more details. I do not use Stabilizer because modern film s already have it in emulsion. A drop of dish washer in the last washing water will help to avoid water spots.

Some pictures using the last improvements: