It's a royal PITA no matter what you do. I tap them together with a hammer and drift rather than squeezing in a vise, but it can still take multiple tries to get it all together right.

Lately I've decided that it's just not worth the time, trouble and chance of breaking something. I've been having them done by a driveline shop, even though I usually have a horror of letting anyone else touch anything on one of our old Volvos. I mean, you can mount tires in your garage too, but it's a lot easier to have a tire place do them...