hey shane, when i was doing at of floors and stuff of that type, i would always use 220 as a finish paper, and try to sand in the same directionas much as possible, then lightly go over it with a some what fine scratch pad, clean the floor very well and wipe with cheese cloth, then you are ready to coat the floor, thats my way of doing it and NEVER had a problem of bubbling , or discloloration,,,, tye!