" only difference in the ADJ. FMU's i have encountered for sale by these well known manufacturers, they bleed boost by means of a bleeder screw & cause a vacuum leak under idle!my method will not due to the ball & spring to seal the air!"
All you need is a one-way checkvalve installed on the bleeder. Just attach a short piece of vacuum hose on the bleeder with the checkvalve on the end of that. The boost reference will vent but the check valve will keep it from becoming a vacuum leak. Piece of cake!