Aaron,
   My '91 GL had the Carat jump seats installed by a previous owner.
Unfortunately he just poked holes in the fiberboard stuff below the
carpet for the pegs at the bottom.  Since I recently had the flooring
pulled up to fix some nearby rust, I finally put in proper mounting
sockets, at least for the seat that we use regularly.
  Bolts with large washers work OK for the bracket/latch assembly.
Since welding the bottom plates and sockets will involve lots of heat,
fire, and burning of undercoating, etc., you might consider bolts for
that too.
   Two recommendations:

Do the best you can to renew the rustproofing everywhere after you are finished.

The tricky part is getting the height of the seat correct relative to
the top bracket/latch.  I would say do the bottom mounts first, and
then position the top bracket so that the seat will snap in properly.

Good luck,
Larry A.

On Sun, Jul 8, 2012 at 10:05 AM, Aaron <a.robinson.lists@gmail.com> wrote:
> I'm installing a jumpseat into an '87 westy and was wondering of anyone had any tips. I looked inside a carat with factory installed seats. It has a bracket welded in on the isle side and I'm not sure what I will find behind the fuel expansion tank in the wheel well.
>
> I'm planning on using some large washers behind the back side unless anyone suggests differently. I did cut the plates for the seat posts out of the floor and plan on getting those welded in.
>
> If anyone wants  to share their their experience, I'd love to hear it.
>
> Thanks!
> Aaron