I was the first one to install Garhauers rigid vang on my H216. The vang is a beautiful piece of machinery and working with the people from Garhauer was a dream. The original vang I ordered was too long. Working with Garhauer, they cut down the vang and took one of the three springs out. I personally would prefer more spring tension but, at least at the time I got my vang, this was not feasible.

Looking at the pix, I have provided three measurements. The the bottom of the mast mounting track is located 38.25 up from the mast step structure. The fore end of the boom track is located 22.75 back from the gooseneck. The length of the body of the vang is 23.

The first couple pix show my mast wedge, how I had to notch it, and the wedge installed.

I may have flipped part of the vang that rides on the mast track 180 degrees but I no longer remember.
The other pix show the vang installed and how I measured the distances.