should also add, the only weakness I have seen with these rectifiers are that the ones mounted vertically may become "swamped" with oil.

if there is too much oil in the system, it will eventually fill itself up with "pure" oil, so if you have to mount them standing, it may be wise to add a service valve between the rectifier and the reg valve where you can connect a hose directly to the compressor suction, so you can manually "dribble" the oil back, or simply a drain valve on the bottom feed so you can "reset" it