Conical Springs. Haven't gotten the final numbers yet for pressures.
You probably know Conical springs vary the distance between each coil from bottom to top, so coil bind potential must be checked at the top coils of the spring.
And the advantage of conical springs over double or triple wound springs or beehive springs is the natural frequency wave generated by the conical spring. Because each coil has it's own frequency, the natural wave is dampened. Then by varying the spacing between the coils, the natural wave is further dampened. Increased longevity and increased performance is the result. The technology of the conical spring is old - we first tried them back in the 1970's (in high performance V-8 motors). The R&D folks we worked with at Cam Dynamic's knew that a pure conical, spring was beneficial, but the available materials and machining techniques could not produce the idea. The idea never got past the dyno. Today, high-quality spring wire and CNC coil winding machines make the conical spring possible. You're the first I know of in our little world here to install them in a set of MOCO heads. I'm curious as to how they will work out. I'll bet the top end noise is reduced - for one...