You will need the base/wall mounts from @Raybo's Ortlieb bag wall mount.
These bar supports allow the use of dowels for individual clips or longer dowels that span multiple bag widths - giving some more flexibility. See the pictures.
If you're using a very long dowel, then print a through-support provided here. You will still need the @Raybo's designs for the dowel ends.
Lay flat, mirror end caps as needed, 40% infill is sufficient, 0.15mm.
Use 16mm M3 cylindrical screws to bind bar supports to the @Raybo mount plate.
I used 4x16mm countersunk screws to attach the mounting plates to wood.
You will want alternate or longer screws if mounting to plaster or concrete.
The author remixed this model.
Added variable bar diameters (8, 10, 12mm) as well as through-bars and caps. This is for the use of wooden dowels rather than metal.
Also added an individual, rather than paired, support wall-mount.