Since a while I have been using Dignan's 2-bath C-41 developer. The color restitution depends more on the second bath, so I have been experimenting different solutions, and these are the results for a 5% solution of Potassium Carbonate anhydrous with 4g/liter of Sodium Chloride, table salt. The film I used was Fuji Superia 100, expired in 2002.
It is said that time is not a problem with this developer, but according to my tests better too long than too short. So I propose 15 minutes for the first bath of CD4 and 30 minutes for the second. All at room temperature.
Still I need to improve the graininess overexposing the film and bleaching/fixing well to remove all silver salts and silver from the film.