Steve, That locking adjustable neck for holding the Dial Indicator is the cat's meow... that is what TCane had when he showed TxBill and I how to do it.
However, it is not absolutely necessary to do the job. If one builds a small bridge over the cam then it is possible to just use the normal magnetic base and the indicator.
It is also very helpful to buy an extension for the indicator shaft. I bought a 2 inch one in order to get the indicator as much in line with the valve and above the cam.