Posted for "Ron Raby" <ronr@advanceddesign.com>:

 Mike
 
 Can you install nut plates on the adapter brackets instead of the seat
platform? and then
 cut clearence holes in the seat platform to give you room for the nutplates?
on the back side where the adapter bracket goes into the original holes in the
bulkhead drill, coutersink then tap those holes this will allow you to thread
in some screws that will become studs. This will allow you to then bolt the
seat to the adapter brackets and then drop them on to the original mounting
holes and install the back with nuts.
 
 Regards
 
 Ron Raby