This is a basic spotter stance here in the southeast, easily visible, hands up in the air, this is a signal for stop, a point to the passenger side would mean turn passenger, and a point to the drivers side is turn driver. Palm out or a closed fist for stop, and obviously we all know the motion for come on. Spotters don't always have to be in front of a vehicle, sometimes what they need to see is in the back, or on one side or the other. I have definitely had a spotter move around my vehicle as I have traversed an obstacle. Also, when using verbal commands between a driver and a spotter, I think it is important that we remember one fundamental difference... you are facing different directions. This brings into focus the failure and accidents that have occurred due to a spotter saying things like "turn left" or "go hard right". It's important to use a better set of references. Here in the south, and I think most places, we use Driver and Passenger, as that is the same no matter which way you are looking. I don't think spotting is to tough.... you just have to keep in mind, who you are spotting, the capability level of both the vehicle as built, and the drivers experience level. You also have to know what is the most concerning to the driver. Is he more worried about ending up with his steering in a bind and popping a birf, or is he more worried about that rear 1/4 panel?
In my case my spotter knows (I typically always use the same spotter - Brad from Mossyrocks Fabrication) that I am more concerned with breaking parts than glass. I could care less about the body of my rig. It's got bumpers, sliders, and a full roll-cage. What I don't ordinarily have on the trail (but I do back at camp) are a lot of spare parts. If I blow a birf, or a hub, then thats 3 wheel drive for me, and it ruins my day until I get back to my trailer, which might be a long way off. All of that to say, use a spotter you know and trust when you can. If not, discuss with your spotter your concerns, and what you think the best line is, don't be afraid to offer input. (this is best done BEFORE starting into an obstacle though), when in doubt, walk the line yourself, think about where each of your tires will be placed at key points, and if still in doubt about what your spotter has in mind, then look for the bypass if available.