: I believe there are brackets that are bolted thru the roof for mounting on
: cars that are incompatible with door or gutter-style clips. I thought that
: this was the 'professional installation.'

Perhaps so, but I didn't see anything like this in Thule's literature.

: Warning -- I'm going to be a bit
: obtuse here, but -- why does a kayak builder need someone else to install
: a clamp-on roof rack?

A very good question, indeed.