Has anybody done an actual test to monitor "variable spikes and troughs in injector pressure"? Or is this a mélange of marketing hype and delusional thinking?
How does a "better implemented return" fix a perceived problem?

Fuel pressure is controlled by a pressure control valve built into the fuel filter. This fuel filter / pressure regulator combo functions perfectly in millions of vehicles, how does it become insufficient to the task when used on a Morgan?

Until I see serious test data on the subject, I would suggest looking elsewhere for a solution.