Try with the usual 38C temperature and you'll see much better colors and virtually no grain. Actually, just the developer must be precisely 38C for the entire time (3min 15 secs). With other liquids you can relax a little bit. I use a warm water bath for the temperature control.
Good work. I will try this too. After mixing up the chemicals, do they have to be used right away? I guess one should have a bunch of colour neg rolls already shot and waiting to develop?