Yeah, it looks like they need to build up the rail to make it wide
enough for mounting plate. The guy who I spoke with charges $85/hr and
said it would probably take 7-9 hours, but of course everything is
different and we'd have to wait and see how long it actually took.

It seemed long to me, but not knowing how to do it myself that was an
uneducated assumption. Does 7-9 hours seem like a reasonable amount of
time to fabricate something to mount the mounting hardware on and then
do a normal trolling motor install?