In my experience, expert and ATS (+other tyre chains) is an oxymoron.

No just Morons mostly.

OK. More explicit about not having different tyres each side. Several times from the 1970's on I've noticed that tyres of nominally the same size had visibly different tread widths and different degrees of tread flatness. That's why I now stick to the same tyre type on each axle.

The amount of money that must go into the development of tyres, and the differing types of tyres available means that to say that tyres are manufactured to have the same grip is ridiculous.

This from people we trust to advise on tyres. i don't think so.