Your over analyzing it. The big lie about sand traps is there is one way to do it. The course I play waters the course and between holes so erratically that the sand traps play different from hole to hole. When you dig your feet in you have to look down and see how deep you go to wet sand. The wetter and stiffer the sand the closer to the ball you have to hit. When you get to a quarter of an inch or so you use a straight blade and play it like a fat shot. The recipe is a full swing will go 1/3 the distance of your club and then roll some. Most people play wet sand too far back from the ball and bounce up into the ball and skull it. When the sand gets dry on top and wet below, one way to play it is to bend your knees a lot and try to skim through the dry part of the sand. This is a harder shot, it has to be real shallow and takes finesse to figure out the distance because done right the ball comes out very easy. Don't worry about the bottom of your club, worry more about staying down with bent knees, having a proper stance and swing plane will make you club do the right thing.