60/40 gas for milk stout

I've just put on a milk stout and I'm thinking of dropping into the Corny keg when ready. I have C02 on the generator at the mo, but I also have a bottle or two of 60/40. Has anyone used this mix for stouts?

 

No, but I don't think it will make any difference most pubs serve all lager with 70/30 or 60/40 @ 35psi ish. And its like home brew served with CO2 @10-15 psi with shorter lines. Guinness uses 25/75 at higher pressure with a special tap to make a big difference.