I never cared for the Stahlhammer endpin, aesthetically or functionally. I've heard that it begins to rattle after awhile, but some people really like it. I did find the need to try something different in the last few years of my doctoral studies, when I researched Rostropovich's influence on the cello music of Prokofiev. I decided, for the sake of experimentation, to try using a bent endpin the way Slava does. No, I didn't go out and buy a Stahlhammer, I took my ordinary endpin to the local "pipe-bender" who I found in the Yellow Pages (Joseph Kavanaugh in Baltimore, if any of you are interested) and gave him the specs as to angle and break point of the endpin. He had it bent in his industrial pipe bending machines in about 5 minutes. It was perfectly clean and put the cello at a more horizontal angle.
I will admit it was strange at first, but I had been preparing myself for it prior to actually using it. I began extending my straight endpin out further and further in the weeks prior to switching over. This was so that I could get used to the new angle. The biggest problem I faced in the first few weeks getting used to balancing the cello without gripping it, though, that I was able to play way up in thumb position with much more ease.
About a year or two after switching I began studying with some Russian cellists who studied with Slava. Pantaleyev changed my entire approach to playing and suddenly EVERYTHING about the bent endpin made sense.
This is what I can conclude:
One must examine the way they hold the instrument. Starker holds his cello almost vertically while Rostropovich holds it almost horizontally. STARK contrast, eh? (sorry, I couldn't resist). So, if a cellist has a bowing style and posture like Starker, it would not make sense to use this with a bent endpin unless the cellist plans to change his/her bowing technique as well.
Paul Tseng