We use a clx 27 pole with a clamp on the end for the camera. We use a two person aproach, I do the cleaning while she does the inspection with the pole, and veiws on a tablet. I found that if you fitted the camera to the gutter pole, the image was very shaky, and ran the risk of damaging the camera. There are loads of deals at the moment with the Gopro as they just brought a new model out, so the older model is a lot cheaper
I use a gopro too and use it on my own whilst gutter clearing...
Clamps onto the gttervac pole so I can see what I'm doing in real time no probs.
Regarding reduceing damage to the gopro case I have it in in a silicon boot that works a treat.
Mind you I did have to cut the boot down a wee bit as I use a larger case to accomadate the lcd touch screen.