As far as what is legal, you can pretty much stand any way you want to, you just can't straddle the ball. What amazes me is the amount of backspin generated by pros as their balls hit the greens. The greens we play are so much faster than most, that a little bit of spin will take off once it starts coming back. Our fairways are so closely cut there is no grass between the club and the ball on contact, which adds to the spin. The balls pros play are also softer than those most players use.
Pros lose a little distance with the softer balls, but they have more spin ratio.
Every ball hit has spin on it, but pros can create more speed with swings and hit the ball more solidly, due in part to the lie. We'd love to play off the bare ground, whereas the average players likes that juicy lie. If you can be in the clubhouse with the lead with the guys giving chase coming to the final four holes, you can pretty much pop your first beer, because you'll probably win. They are just brutal finishing holes. The British Open is a unique experience when it comes to majors.