Can't help with the colour chemistry,but I would advice that you use 300ml instead of the 290, that extra 10 ml can make life a lot easier, and it alwaus better to have a little bit more in the tank as film reels can slid up a tad, and you can the top of the film bot developed enough, also, as I understand it, all colour films in c41 have a standard developing time, so you don't need charts as you do for black and white film