I think you should ask Dukes formally for a component maintenance manual, parts list, instructions for continued airworthiness, theory of operation and overhaul manual as owners of the aircraft part and LOBO.   Its part of what's required to maintain airworthiness.  You probably won't get it but you should have it as builders of the aircraft.  At a minimum, Lancair should have it, they did the engineering and should know all the requirements.  Anyone getting an airplane from Lancair with a Dukes valve has to have the instructions necessary to maintain airworthiness.  Okay, that may be the FAR for type certificated aircraft but the Lancairs are type certificated in Canada so I guarantee those manuals have to be available for Transport Canada and Canadian pressurized Lancairs (although they might not know it). This stuff is not supposed to be secret.  I'd send a missile to Dukes and get Lancair to organize the materials.   No Evo buyer is going to be excited to find he can build the airplane and not have data on the pressurization components.