Of course practicing ball position and wedge swings at the range isn’t exactly like launching scoring shots on the course. In practice every lie (or nearly every lie) is perfect. In actual rounds imperfect lies abound.
Adding to the difficulty is the fact that Shinnecock’s greens run faster than Flynn originally intended. Shortly after he redesigned the course in 1931 (Shinnecock dates back to 1891) the USGA began measuring how fast and far balls rolled on level putting surfaces calling the measurement “green speed.”
And you don’t have to change the length of your motion — you can keep your stroke the same length as it normally is and still transfer less power to the ball. The shot will come out a little softer than normal but with the same characteristics: a little bite on the first bounce then a release and rollout down the slope.