I removed the clips (since it won’t fit on brook b17 and replaced them with rubber straps. It works well and doesn’t move around. I rode my bike on a gravel road for 170 miles, and around 5 miles on an ATB trail. It was very reliable.
After packing, I secured it with an additional strap just in case (see pictures). To install the straps, you have to lift the rails with a pair of flathead screwdrivers. So, no need to buy another seat post or use an uncomfortable saddle.
by Savings_Bed1592