On the silica gel strips, I use them in Olympus and Canon housings but have yet to need one in a GoPro perhaps because of sealing it in AC most of the time. Anyway, I would get the small kind, be real careful about not interfering with the gasket seal on the housing. There may be room between the back of the camera and the housing door for the silica gel tape.
Working on some of the HD shark video now, should be pretty interesting. Air rings rising up to the boat through a cloud of sharks, sharks hammering into the diver and camera and a lot more. Feeder putting a gray "to sleep on the bottom," not sure how he does that? You could get real messed up on one of these feeds if you don't listen to instructions. Even if you do, there is always the odd bad day. The feeders and photographers wear partial mail suits, don't want a shark biting an unprotected area. Still, it is pretty mellow, the first videos I shot might put you to sleep. A couple of hours of sharks swimming rhythmically all over like a bunch of cats walking around a food bowl. This time, the sharks must have been a bit less mellow. Banged into me a bunch of times and I wasn't even holding fish.
A real short video from the first time a couple of months back appears HERE
Should be a lot different this time.