I have a rather grubby copy of a Kenyon’s 1956 Fuel Lines List of component parts. The most popular sizes seems to have been 1/4″ & 3/16″ bore.
Even the most greedy Scott has got to do better than 30mpg flat out, (petrol that is although not necessarily oil!), it has to, hasn’t it?
My addled brain reckons that is >200cc’s/min, a volume that 1/4″ pipe will handle easily. There are a lot of things that will conspire to slow that number down though, the head of fuel, bends, corners, fittings, vibration, just about everything in fact but that’s life ‘aint it?!!!.
If you can supply an email address I will try to send you a scanned copy if it’ll help.