I am not sure what a B72 is. I have Brooks Conquest saddles on most of my bikes, that lacks the loops but it has springs. I run the straps through the springs for my Carradice bags.

I do not like the bag hitting my legs when my pedals are at the lowest point, so I use a stem (with appropriate shim) and a short piece of 1 inch dowel, sprayed black to hold my Carradice Pendle further back.





Decades ago I got some of those small loops that you cited to add to a saddle frame, I was not very happy with them, they have tiny little screws and they would slide on the steel rod on the frame. No longer use them. But maybe you will have better luck than I had.

I have owned a Nelson Longflap for years. A few months ago when the US Dollar was really strong, I tried to figure out what I might want to order from Europe to have later, bought the Carradice Camper at that time but have not used it yet.

If you use a Carradice bag, I added a sheet of cardboard inside it to give it better structure, that worked so well that later I cut a piece of Corroplast to use instead, that is the white inside the bag in the photo below. It is just bent in a U shape inside the bag, not physically attached. It gives the bag much better shape and when mostly empty it does not hang down like an empty pillow sack.