Actually, it sounds like the pressure will be applied to a few points and two sides. And as long as the top of the tank is level, the tank is supported evenly. From the sounds of it, the back of your stand will be fully on the floor as well as the left side. If you're worried (I know, I'm like that too!)cut your own shims. Figure the slope and cut the shims to run most of the length of the front and side of the stand. That way the whole stand is supported. I placed shims along one side and most of the front of my 90g. I used half a dozen or so. Kind of a pita, but once its set you're o.k.. Oh, and the carpet will settle, so I would fill it with water and let it sit for a day or two, then re-check level b4 adding anything else.
Good luck!
Good luck!