A consistent Setup at Address is an important fundamental in putting. It does your putting no good to keep changing the way you stand to the ball. You need to do the same thing every time you putt.
While there is no one correct method, trial and error has lead to a degree of sameness among current players in the way they set up at address.
Golf is a game that puts great demands on your back. The more you crouch over the ball, the more the posture muscles supporting your spine will tire.
The modern tour pro stands more upright than the pros and leading amateurs of the early 20th century.
With the tilt from your hips around 45 degrees a taller position is less demanding on your back. It also allows more room for your arms to swing the putter.
Aiming accurately is a problem for all golfers irrespective of their handicap. Because you stand to the side of the ball and not behind it when you putt, you lose the advantage of binocular vision.
The optimum head position for aiming beside the ball is where your forehead and chin are horizontal to the putting surface. This allows you to swivel your head to see the line of your putt rather than to turn and lift it.
Today the popular method of using the logo or line on the ball, or spot putting to an intermediate target, has resulted in more aiming taking place from behind the ball than beside it. This has reduced the dependency of a flat head position for accurate aiming.
Tour pros typically hold their heads higher as a result of their upright posture. They look more down their cheeks at the ball rather than directly down on it.
The recommended method for aligning your feet is to place them level with each other and parallel to your aimline.
Before greens reached the speed and consistency of today, many golfers set up with an open stance and with their shoulders turned slightly towards the hole. Because of the slow surfaces, they used a wristy putting stroke to get the ball to the hole.
An open stance makes it easier to sight down the line, and is used more for long lag putts where some hinging of the wrists is needed. However, for putts where direction is more important than distance, there is a danger that you will putt down your shoulder line and then use your wrists to manipulate your putter back on track.
The Setup at Address has changed over the years, but the object of the game of holing out in the fewest shots has not. Putting therefore still allows for individual expression to get the job done.
It is still a case of 'How Many' not 'How'.