>Does anyone know whether is there a source for the wooden
>wedges you insert between the yakima or thule bolt-on rain
>gutter sections and the poptop.

Steve,

Not entirely sure what you are describing here but I assume that you wish
to put a wooden wedge in in order to have the bolt-on rain gutter
sections mounted exactly vertically.  If going this route I would imagine
that you would have to put an identical wedge on the inside as well so
that the mounting bolts would tighten against parallel surfaces.

On the 81 Westfalia that I used to own, I installed the Thule bolt-on
rain gutter sections without any wedges.  There was a rubber "gasket"
that fit around the bolt-on rain gutter sections providing a cushion
between the bolt-on rain gutter sections and the pop top.  A metal
backing plate was mounted inside the pop top which the nuts tightened
against.  My gutter mount rack uprights attached to the bolt-on rain
gutter sections with no problems in seven years of service with this
configuration.

Hope this helps.  Good luck with your installation.  The hardest part for
me was getting up the courage to drill the holes in the (expensive) pop
top!!!

Tony

Anthony L. Mourkas
Hampden, Maine, USA
1984 Vanagon Westfalia
1990 Passat GL
1991 Jetta Eco Diesel