I think you don't understand the physics of a road draft tube.
A PCV system draws gases SLOWLY out of the crankcase, through the carb and burns them eventually. Its purpose IS to keep that stuff out of the atmosphere. Why else did it only appear on emission controlled cars? On 60s Fords it was sometimes a $5 option but later became mandatory by first CA and then the feds.
A road draft tube hangs down and is designed such that the moving air flowing past it causes a partial vacuum (exactly the same way that a carb venturi works) that sucks the gases out much more quickly since there is no flow restriction as in the PCV valve, etc. Some systems have additional restriction after the valve to further impede gas flow so as not to flood the intake system with blowby. The crankcase will be much CLEANER with a road draft tube than a PCV. If anything, oil change intervals would be LONGER using a road draft tube than a PCV. I doubt it actually makes any difference for oil changes.
If the engine has blowby (which they all do to some extent) then it has to go somewhere. Replacing the PCV hose with a breather means its going to make an oily mess on your valve cover. The road draft tube would dump it into the air below the engine. Doing away with the PCV will not help performance in the least so I fail to see a reason to work very hard to get rid of it. If blowby is so bad that its plugging the PCV, etc., its time for an engine overhaul. Smoky old cars give the hobby a bad name and give those tree-huggers an excuse to want to work harder to make old cars illegal which some of them already would like to do.