Thanks Dennis and Jack.

I do have a 1.5" lift.  I'm using the Gowesty Fox shocks, and I had
assumed the extension would be the same as stock, but I realize now
there's no basis for that; I will check with them.

> The later axles do not use the cone washers on the CV and it is normal for the CVs to sometimes slide on the splines.

Thank you, good to know this is normal.

> You may want to consider the 944 CV joints.
> http://www.t3technique.com/suspension-and-drivetrain/drivetrain-parts/cv-joints,-boots,-etc/944-gkn/lobro-cv-joint-kit.html

My problem seems to be axial length, rather than angle.  Do you know
offhand if these allow more travel as well as more angle?

> The GKN's hold up best, they are OEM, and will last another 30 years!
> https://www.fcpeuro.com/products/vw-axle-shaft-assembly-gkn-251501203gx

Oh, good to know GKN makes the complete axles.  Looking at the part
number (with the extra G on the end) and fitment years, this appears
to be the newer, shorter axle, and I'm not seeing a GKN version of the
longer axle.

Thanks all...additional suggestions welcome.

Alex