David,
For some reason the wedge debate is one of those Duckboats.net legends that seems to have no compromise... ; )
Yes, you could install them like that - Eric P uses tape when he "dials" his wedges in if I'm not mistaken (he affixes them with epoxy later). "3M 3200'ing" some wedges on the back would work. It wouldn't hurt.
People will send emails and tell you that wedges will compromise your boat's speed or even safety -- they won't. Putting 100 lbs in the bow of a small boat like ours is a huge amount of extra weight to carry around. Weight kills speed & performance and in my humble opinion - safety. I wouldn't want to come off of a 4' wave nose down with 100 extra pounds up front - dumb.
A wedge acts like trim in an airplane's aerolone (need spell check). Just a little nudge in the other direction and it adds a stable boating experience at any speed. In my experience, the wedge effect is killed at slow speed. In really big waves, I slow the motor up, adjust the motor tilt and I can get the nose right up, like a displacement hull BBSB. The wedges are NOT working/deflecting at that speed - clear as mud?
No, you do NOT need to fiberglass. Their placement is in a sacrfricial location. My center keel takes the punishment of a beaching, the wedges are tucked up and out of the way. I still don't have a scratch on them after 4 seasons and when I do scrape a rock, which I will, I wouldn't want fiberglass hanging off them, that would be a mess. I wish I could post pics of mine, but I'm a loser when it comes to that stuff.
Good luck.
A>