The original recommendations were for a gravity fed day tank which can be filled by any one of several means from other storage.
That being said any pressure feed system you devise must consider that the fuel pump moves the exact same amount of fuel each stroke. What changes is how much goes to the injector and how much is pushed back the inlet line. Those clicker type pumps use valves that do not allow reverse flow. Thus you must provide a means for the fuel to go backwards in the line. This can be as simple as a length of rubber hose. What you cannot ( or more exactly should not) do is hard plumb the entire distance between the two pumps. Sure as hell I say that someone will say WTF?? I did it?? I did not say it will blow the pump to smithereens the first stroke but common sense says that if the pump must expand ridged tubing that the stress on the pump element, rack, cam and push rod is all dramatically increased not to mention what it is doing to the fuel pump valving. Secondly the pumps were just plain not designed to have large amounts of head pushing fuel to them. Any internal leaks at the element will be increased as head increases. You want the least amount of head pushing on the injection pump that will provide the needed fuel. Every one I know who has gone this route with work engines that run daily has reverted back to gravity feed,,,,