Cuban8
I have edited my original post – please read it again and see if it makes more sense now.

“The leak is at the base of the pipe where it screws into the metering element.”
You mean the pipe joint at the swaging? If so you have no leak in the delivery valve assy. Fit the pipe to the pump first and nip up gently, then to the injector finger tight. Finally tighten at the pump followed by the injector. It is easier to fix a pipe leak at the injector than at the pump.

“the high pressure fuel is sealed in the stack of parts” That is correct


“There should be no fuel running around this stack and no need for a high pressure seal on the threads of the pipe?” That is correct.

Any Fuel Injection shop should have those washers, give them the sizes I quoted.

__________________
Beagle