Helgenson E tool Or Similar

Looking for an Helgenson E tool to measure the pushrod pinch wall thickness for cylinder heads. It looks like finding this tool is darn near impossible. Looking for something similar or even homemade that will work. Need it because I am porting a set of r/t cylinder heads and was smoothing out the pushrod bulge but then noticed an imperfection in the casting where the pinch is slightly thinner.