PCV systems were not added to keep the crankcase/internal engine cleaner, but were added to reduce hydrocarbon pollution. There is a benefit by adding a PCV to a 226 and that would be ensuring crankcase vapors ( unburned gasoline and condensation) are drawn into the intake and burned. You would be better to design your system like the OEM's and filter the air going into the crankcase/oil filler by connecting to the air filter. The oil bath air filters are marginal at best, so using a paper filter would be better. I would use a PCV valve from an engine of similar displacement. PCV valves are sized by air flow. Too large an orifice in the PCV can cause some idle issues, lean idle, but not a large concern because carburetors generally are rich at idle.