I was in a hydraulic hose supplier today, and asked if they had anything like copper washers. He directed me to a shelf full of copper washer of all sizes, (maybe even big enough for the compression changeover valve, and as small as the one at the bottom of the injector nozzel) that were for english threaded hydraulic fittings...
If I can find some dimmensions, i can go back and see if any of them are a fit.. The supplier is a national chane wide store, so shoul be available across north america.. I previously got some push on hydraulic fittings to replace the banjo bolts on my dodge fuel system.. no more loosing a washer into the abyss of the engine compartment.