Power Valve Selection: The Definitive Answer

Got the 10.5 PV in, ready to run, just haven't had a chance to road test it. In the meantime, seems there's a bit of chatter about power valves and it got me wondering if there was any feasibility in an adjustable preload power valve? Adjustable within a certain range, especially above 10.5" up to 14"? Would be an engineering marvel!