35 is better in my eyes, they will become less soft as the temps drop. Anything above 35-40ยบ outside and they wear quickly and don't do there job as good, they excel in cold temps.
As for that stocker guy, we have tons of people come in with different rims they want thrown on the car for winter and most never have sensors. My work is not a corp. store, so being a private owner has it's perks and we just don't care and leave it all in the customers hands for checking pressures etc etc.