Dack, I have filmed a lot, to do board reviews and have tried several different mounting theories.
Never had an FCS mount, but I would like one. So I used the GoPro "stick on" mount.
It works very well... the only time I ever had an issue, I fell off the nose really hard and my knee actually ripped the mount off the deck. The glue never failed... it actually ripped the paint off the board.
The deck mount has the inherent problem of "bad angle"... but gets some fun/useful video every now and then.
I am horrible with the paddle cam.
My best videos come from my headmount cam... if I have it positioned properly on my head.
I am regular foot, so I always mount it on the left corner of my forehead... aimed slightly down.
This vantage point works equally well frontside or backside.
To visualize what the camera sees:
Stand against a wall... pretend it is a wave face.
"Surf" the wall.... regardless of which way you are surfing.... the cam is looking at the wave face, directly in front of the board.
If you point it at the right degree "down" it will capture where you are going... the board and the wave face, for a good look at the action. Hard to get it all right... but when you do, the video is worthwhile.
Here are 3 examples of how the head cam mounted on left corner of forehead - regular foot (right side corner of forehead if goofy foot)
Frontside or back side.... the viewpoint is the same
plus the benefit of filming your buddies as well.