As well as shaky your leash tends to wrap around the pole on wipe outs and pulls it down. Have used in this position without a pole lot more stable and get cool view of spray flying off the rails
Check out some of DJ's vids and you'll see his rig (no that's not a euphemism!!). He gets awesome angles & footage, though you might need an extra GoPro!!
No doubt that one would work... until it doesn't. Looks to be way too many metal and moving parts that will inevitably corrode through exposure to salt water. Even the GoPro suction mounts are vulnerable. The beauty of DJ's design is that it is all PVC and will last for a long time. The down side is you go through a lot of duct tape every time you use the mount. Mind you, I wouldn't trust a suction mount in the surf or on a downwinder without some back up duct tape holding it on.