I did a similar thing when I moved a tank a couple of years ago. I tried not to disturb the sand bed as much as possible, but the water swishing back and forth still mixed it up pretty good. It ultimately worked out but, it was only a 60 gallon acrylic so fairly light. Don't think I would try it again with a glass tank just because if the weight. Secondly, if I were to do it again, I would take out out the sand rinse it well in some fresh salt water and then reuse it. You would most likely keep much of the good bacteria, while getting rid of the "crap" that has built up. Re-dose it with more friendly bacteria to start it up again.
Trying to keep the sand intact is sort of a lazy man's way to do it, I wouldn't recommend it having done it once.