I would strongly advise against moving a tank that size when it is full, even a few inches. Definitely drain it down as much as you can before doing it, as it is just not worth it if the stand breaks. The stand is supporting an incredible amount of weight, which means a very high center of gravity, as the stand is nowhere near the same weight. As long as the force is vertical, that is coming straight down towards the floor and is pushing against the strongest part of the stand, there is no problem. When you move it, the tank is likely to move slightly further than the stand, and the support beneath can't handle the weight at a slight angle, and down comes the whole thing.