Im 8 up 10 back to tank with reg after the carb. Mallory 140 with their regulator. Been running this setup on past 2 cars for 15 years. No other way I would do it
Makes no sense to me why the return line would need to be bigger than the feed line; there's already going to be a reduction in volume from filling the carb, so having it the same size should be sufficient... IMO.
EDIT: Not sure of the manufacturer, but here's another schematic that's similar to what I posted above.
