The dropped gun butt (below hip) is required in International Competition, I believe.
As far as skeet itself, a cagey old guy I knew taught me to line up so that if I mounted the gun, it would be pointing at about where I wanted to break the target. (Obviously, this doesn't work at trap). Since I wanted to break targets in about the same place, no matter what station I shot, I always try to smoke 'em around eight, or a bit before, thus, I would always point at eight using this method.
I have seen lots of shooters change stances between high and low house birds from three to five. Some of them were/are a bunch better than I am. I have tried this too, and it works.
I agree that to really improve, you need to watch alot more targets than you shoot, and having a good shooter peek for you helps most. (Look over your gun as you shoot).
At skeet, keep the gun moving, and swing through the shot. Trying to snapshoot, or stop the gun at the shot, will not break many birds. Be smooooth. I worked as a trapboy when I was a kid, and I can't count the targets I have watched, at skeet and trap. Hundreds of thousands, surely, maybe more. (I just did a calc and I have pulled or scored 25,000+ birds over three days more than once, at trap tournaments).
I never took either game seriously enough to get beyond 'A' level shooting, but I have known and watched some of the best shooters this country ever produced. The good ones were the ones who made it look easy. The best ones were target breaking machines. For trap, you have to find the rythym, and a bad squad at trap will screw this up. If you want to be serious, shoot with serious shooters. If your just out for the company, don't get serious. All of the shooters I knew can do both, when appropriate.
Above all, I always felt that trap and skeet were two shooting sports where you could really get to have a good time with your competitors, while you are shooting together. Some of the finest people I have ever had the privilege of associating with.