Here's an idea, take the car for a thrash and get it nice and warm, jump out and feel both rear tyres. I doubt you'd be able to distingush which was warmer. Take into account the cooling effect of the air going past it, I doubt it makes any difference at all.

Guessing that manoeuvre was required because the driver's window wouldn't close properly?

Just another fraction of a G needing to be pulled...

Whilst we're on this subject, in my experience it's just as likely that you'll find a nearside rear arm that's out of tolerance, so wonder where the idea that's it's only the offside has come from?
I know that I've corrected the alignment on both sides and if anything, it's the nearside which seems to need work most often.
Easy enough to check anyhow, once you've got the string lines out to set the tracking at the front end.

ken
( Re. exhaust gas having an effect on how a tyre wears: it's a bit too early for April Fool's Day, isn't it? )

Been carrying an anvil in the front passenger footwell again?