Source for slip yoke for T5

Ok, still battling my nasty vibration problem on my 66 w/ T5 (see my earlier post). Next step is to replace the (worn) slip yoke, tail housing bushing and seal.

The bushing and seal should be fairly easy with the part numbers I found on various sites:
National/Federal bushing/seal kit 5202
Tailhousing bushing Clevite 02105
Rear seal 7692-S or 7052-AA

I am not so sure on the yoke. Several questions:

1. Are all yokes (that fit a T5) the same? Splines, diameter, length, u-joint seat? Or what all do I need to measure before I order anything?

2. Where can I buy one?

As I live in Germany things are a little more complicated (I don't know all the 'usual traps' to check in the US ....) but I am coming over in a week for a vacation and would like to order the stuff ahead of time to have it available when I come to pick it up.

Thanks for your help,

Stephan