Very close to my "napkin" design
I aimed for about 180deg/sec at full speed, but couldn't quite get there with the finite available sprocket ratios.
We limit the 775s to 60% of full command speed, and the PID loop still does a great job of controlling them.
I hadn't done a stall calculation, we had been planning on using a DeWalt transmission with anti-back-drive pins, but found that the pins didn't like it when the arm was powered down, so we removed them. This also has the side benefit of being able to move the arm without powering up the robot or disassembling anything.