The design of the valve is so simple it's not that hard, the complexity comes from having to make a feed system too
you've spent all these years building this... and now you are stuck at the same problem that I encountered
a 1/2" spool valve or a QEV + spool valve combo and a timing circut would work as good as this - if not more reliably... I even found a way to make it go full auto without having to fiddle with electronics
I've never quite understood your personal crusade to build this... what's the point of minimizing wasted air when inevitably the valve will have lower perfomance than a qev...?
tell me...couldn't you just accept minute loss of air per one cycle, could you??