John,
I have Thule's mounted to the glass top with the fake rain gutter
attachment.  Is this what you are trying to do???  I got the tallest
feet available and the widest bar possible.  It works out great.  Let me
know if you need more details on part numbers...I may be able to find
them.  The thule catalog should describe what you need.  At least you
bought it at REI.....never a problem with returning anything.  Ask
around, you will probably find a sales person with more knowledge about
racks....

Chet
-- 
Chet Douglas - CRD Consulting - Peripheral FW,SW,and Drivers
(541) 754 - 1817