that will be a good Support for a pair of saddle bags !
Best way is to fix them under the seat / bench. That will allow to open the seat without removing the bags.
Might be a bit of testing and trying and some time to get the Connection Piece into shape.
Right Hand side:
Top of bag should be below the open seat or expressed other way round, you should open the seat and then fix the top of the bag right below that. Left Hand side adjusted to same height.
Hopefully the bags don#t touch the exhaust. Bags will not withstand that for Long. Plastic ones are ruined after one ride, leather bags will stand some time but you should avoid that.