I have used both the Tetenal/Arista C-41 and the Rollei Digibase C-41 using the above guidelines and have not had uncorrectable color shifts. I process 20-25 rolls per 1-liter kit.

I use an "electronic enlarger" so it's hard to tell about the color shift since color balance is easily correctable.

Hopefully there is someone here who still uses an optical enlarger that can share their experience.