Has any one SUP'd with a chest harness and camera? I was wondering if it is just a flurry of arms and paddle shaft or does the camera get in the way whilst paddling?
Have a Go Pro Chest Harness but like you I think it would be too much arms & paddle. So I have never used it.
Use a surf-helmet mounted camera. Gets a good perspective of waves, board and a little bit of paddle & arms. So far so good. 
I've used the GoPro chest mount a couple of times and didn't like it.. There was too much movement and made you feel sick watching the footage back.. It's a good view for when you're not paddling hard and stay upright but once you lean forward the mount doesn't seem to hold tight against your chest and the camera moves a bit too much.
DJ
Had no real issues with the chest harness. Just that it makes waves look smaller. No real depth perception.
But, prefer the footage to the Nose mount.
A few bits of this I filmed with chest mount. Goes ok. As its been said, flattens the waves out.
If you are using it for surfing, it is only good for waves surfed on your forehand. On backhand waves all you get is footage of the beach.
Thanks everyone, I would be using it for flatwater or downwind paddles as I am not at a level to try surfing. Still might be an option.
Here is my version of back-cam. Homemade out of old broken paddle and kite harness. Cost: 4x nuts and bolts + 10 dollars for a local shaper to add a little foam to handle.
Short vid here:
