Adding another inexpensive method to the solution list. Rubber bands don't last long in our 100 degree Florida garages, and I can't use the spring method since I use the Powder Check Push Rod hole for my endoscope camera.
I attached a Double Split Shaft Collar with 1" Bore (Amazon link) to add about 3 ounces of weight to the switch section of the MBF dropper assembly. The brass section doesn't have a the clearance, and I didn't want to obstruct the clear tubing part. You may find the collar it at a local hardware store but I went with the Amazon choice. Works perfectly now.