OK, so I've got some skills, some tools, and I can measure my front spindle
to the 1/1000th of an inch if I wanted to.  Butttttttt, let's say,
hypothetically, of course, that I wanted to play around with different
hubs/discs from other VAG products.  How would I know what size bearings to
use in the hubs?  How does one measure that?  It's a tapered area.  Is
there a place that I can cross reference which hubs had which size bearings
so that I could, in effect, always find a bearing that matches the Vanagon
spindle but then I could reference the OD of the bearing to match whatever
hub I choose?

No rush...

Thanks,

TJ