I spin my Pro v1's in a Check Go that finds the heavy spot. I then mark that line on the ball by going over it in a marker so it shows up better. I tee the ball with the line vertical as well as putt with it that way(easy to line up also). The heavy spot is not always on the seam. It is amazing that the ball ends up heavy side down in the fairway after teeing off about 75% of the time. The ball seems to fly straighter and put better this way.