Has anyone used a CO2 cartridge to power the air shifter since space is so limited on the vrod? If not that who/what has smallest bottle and regulator that might fit in one of the small frame bags next to fuel cell? I tried one of the Pingel electric shifters and could never get it to function consistently. A friend that races a lot commented that was the reason they never seen on serious race bikes. That his observation and my experience supports it.Thanks for any help!