Yep - Mag floats are great. As mentioned watch the sand.
I like to do the side - front - the other side -but stop about 1/2 inch from the sand. Then when all glass done, run the magnet carefully along the sand line all the way back around the tank. If you do happen to pick up a particle of sand, and miss seeing it, if you do scratch the tank it will only be at the sandline.
So far - no scratches.