If it’s the bags pictured you have, aren’t they using the same hole in the frame (just below the saddle strap) that the Fehling also utilises? I imagine you’d have to fashion something so that your OEM racks stood outboard of the Fehling rack (spacers etc), if you wanted to use both together.......wasn’t @ChopperCharles looking at something similar, once?
Welcome, by the way, new guy.
Ben