When running Carlsberg and John Smiths on 70/30 i noticed that the john smiths was dispensing very slowly however the carslberg was alot faster almost perfect in fact. I still got a great pint out of both.
The setup was via a flash cooler and lines ( Not a a Python) and a Mixed gas regulator.
I checked all the lines for holes or bubbles showing and didnt find any leaks ect, I also checked the regulator pressure and it hadnt dropped.
Apologies as I am a newbie to all this 🙂