as far as where to put the sand ballast- the saw is causing the vibration and transmitting this energy to the floor. Therefore, the weight has to be on the saw. I added a shelf on the stand of my saw secred it put the bag of sand in a plastic garabage bag and finally put the whole thing in a pillow case and closed up the bag. The reason is if the sand bag starts leaking Icould contain any splill. Putting the ballast is about the only way to really resolve the problem . Location in the room is very important also,Place the back of the saw close to the wall for extra added floor support,rather than in the center of the room. next try two bags if needed. This has alwasy solved the problem. Good luck David