Harold Swash is the putting guru of Europe and is the inventor of the C Groove technology of the Yes! Putters.
I had somebody e-mail me about Stan Utley's putting philosophies. I've never read his book 'The Art of Putting' but have some pretty decent knowledge of what Utley endorses. One of the reasons why I prefer Geoff Mangum over Utley, Pelz or even Swash is that he basically doesn't have a method that he believes is THE way to putt. In fact, in Mangum's book 'Optimal Putting' he essentially states that as long as the putter face is square to the target at impact and about 3" after impact, all the rest is just window dressing. Pelz is a SBST advocate. Swash likes the arc stroke, but wants a wide stance and the golfer trying to hit up on the ball to get the ball rolling with as little skid possible. Utley is an arced stroke advocate.
One of the things I've come across with Utley's philosophy is that he believes that golfers should add loft to the putter because he believes that golfers do not play with enough loft on the putter. But according to David Orr's studies on putting (and he researched 677 subjects including 50 Tour pros), most golfers actually have too much loft on their putters. From my observations Utley, Pelz and even Swash's philosophies are not all that scientific. Pelz used to work for NASA and while he did have a scientific approach to his philosphies, they often were woefully flawed or had such a small sample size that no self respecting researcher or scientist would publish those findings.
It appears one of the goals of putting is to hit the ball solidly off the sweetspot while hitting slightly upward on the ball and producing as little skid as possible. I guess it would be very possible to minimize skid or eliminate it all together by topping the putt, but that would destroy speed control/touch. So minimizing skid should happen when the ball is struck solidly and is part of the golfer's 'natural' putting stroke, IMO.
In the end, it's not to say that they (Pelz, Swash, Utley) are exactly wrong, but it's too say that like the golf swing and like clubfitting for full swing golf clubs, there's almost countless ways to do it. The C-Groove technology (and Taylor Made and Rife's groove technology) does seem to work extremely well. But like the golf swing, there seems to be very few imperatives to the putting stroke.