points from comparison of Zach Johnson and Tigers

http://www.youtube.com/watch?v=eUl82HFvFVM

1) At address, putting more weights on the left side is normal practice for tour players. How much is per player's preference. This address characteristic will affect the spine angel at the back swing and down swing.
2) during back swing, leave side is left un-moved, because most players have difficulty to move from right to left at down swing.
3) Zach puts more weight at the left side, left side doesn't move at back swing, causing spine angel tilts more to the right. At down swing, his spine angel doesn't move much.

Tiger has more neutral weights at both sides, left side moves a bit to the right but not much at back swing, spine angel tilts a bit more to the right but not much. At down swing, his spine angel moves more to the right side due to bigger lateral move (spine angel move is because of head is still while hip move laterally) .
4) The lowest point of the down swing is determined by the location of the lower spine