lights for gopro3

[jbjclj]

I'm not familiar with that specific light, but I do know that backscatter would be a problem when the light is so close to the lens.
400 Lumens is very weak as well. It would be effective only for night dives or in daytime less than a foot close.
It would be best to get a pistol grip with flexarm and attach a stronger light such as a 800-1600 lumen. You can find good lights with those specs at perhaps a slightly higher budget, but it's worth it.
The setup you suggested won't be so effective in my opinion.
Note that the Ultrawide angle which fits the GoPro's view angle is even less Lumens - just 270..

 

[timz]

This is what I got. Arms are easy to adjust when required.

Got the lights from Ebay. ARCHON D11V.