Wow! This topic has really meandered. Anyway, regarding running in, the page from the instruction manual, as included at the Golden Flash home page is attached. My book by W.C. Haycraft says keep it below 45 mph in the first 1500 miles. Almost impossible, too much temptation. (But I've managed to keep it below 55).
As for wet sumping, as long as it is not excessive and there is a good amount of oil in the tank above the supply line, I start up and let it idle (or a bit more). At first the return to the tank is continuous and, after a bit, it's sputtering properly again. Thus, I am not challenging the engine with a sumpfull.
Regards,
Richard L.