Man, that's great! I'm still stuck on the first line -- what's more important than the stud or bolt pattern? (nothing: that's what)

None of the original wheels that Volvo used rely on the center hole to provide or augment the strength of the mount. Some of the later models, like the 240, are hubcentric - but this still doesn't provide any mounting strength, reinforcement, etc.

If the center is small enough to fit inside the opening in the wheel, good enough. If there's some problem with some other element (offset, etc), that's a different issue.

Best,

Cameron
36 Volvos and counting
Rose City