When I play liedowns, I usually lay halfway on my back and on my side, with my head in the tallest end of the barricade. The leg that is against the barricade, I put alittle bit under the barricade. Then use your abs to get quick peeks and snapshoot over the top, this should be coordinated with backguys. When you are halfway on your side you can also shoot down on the tall end where you have your head, you can get your marker close to the ground and shoot lanes, sometimes there are blindspot here. You can even wrap you bunker and get greater angels, sort out all this when walking the field. When you wrap your bunker be fast, or you can very well be out of there. The Disadvantage is that the liedown is hard to get out of, unless you go to your stomack and speedcrawl to a nearby bunker.
The snake is great!! I play by speedcrawling on my stomack, getting my backguy to keep his mirror in when I have to pass the "v" in the snake. You can put him in yourself, and then move fast. Now to actually shoot anybody, coordinate with your backguys where the opposition are, and then try to have them put them in, go over the top and snapshoot. I do this both in the above mentioned way, but often on my knees, really tight!! The backguy right in front of you is the most dangerous guy, if your backguy puts him in, you can do serious damage... On the snake work fast so you have the momentum, and you can surprise your opposition. First time you come over the top and take someone out, great chances are the the opposition are looking to mug you out of there, so work fast....
This is my style, hope I helped