That is a great article, thanks for posting. I'm not sure if twist is an issue for the SOHC or not. One thing that argues for the latter is that each cam is only running 8 valves, not all 16 like a normal V8 would be. Also, compared to the spring pressures they're running in Pro Stock, even the pressures I'm running on Comp's biggest cam and the heavy Manley valve are way down the scale (600 open vs. 1000 open for the Pro stock engines). Nevertheless, I'm sure there's still some gains to be made with a stiffer core.
I don't know if Bill's machine can look at relative valve motion or not, but I think he is probably restricted to one cylinder at a time for measurements. Maybe he will chime in here...