Another point about the pony bottle mounting which was the main reason I had the valve up in the first place. With the valve down it is right next to the bottom dump valve. There is the potential for the dump valve release chord to tangle with the IGS valve and its dust cap and tie and even hold the dump valve open. If found this cause confusion and problems today. I'd recommend removing the dust cap from the pony.
I would recommend getting rid of all dust caps, both on the regulators and tank valves, before you get in the water. Put them in your regulator bag when you assemble your gear. They can be an entanglement hazard.