It's not rocket science here..in the old days they installed a "road draft tube" off the back of the engine or on the filler tube, worked OK but those old motors always had a lot of blow by and
oil going through and the
oil fumes just went out the back onto the road.
Probably the most important concept is good ventilation to reduce pressure buildup inside the engine. Valve cover vents are good but will let some
oil pass out onto your motor and create a mess especially on long drives.
To me, the best set-up is a negative pressure through a pcv on the back of the intake manifold and into the base of the carb., along with two valve cover cap vents. this set-up seems to work pretty good and doesn't blow out gaskets and cause a mess.
Anyway, this is just my opinion...Bill