Riser vents

My 1920s 5-story condo building in Washington, DC has an old one-pipe steam system with risers that have air vents installed just below the ceiling in all of the top floor units (I assume the risers are capped just above those ceilings?). Some of the air vents are Gortons, Hoffman 40s, and Hoffman A1 adjustables. I suspect many of them do not work properly, as many have been painted over and others show serious corrosion. I'd like to replace all of them with the same air vent, so my question is should I just use a bunch of Hoffman 40s, or should I look to larger ones such as Gorton Cs or Ds.
By the way, I have the "Lost Art" and have read the part about venting risers, and have looked through all of the previous postings on this topic, and couldn't find an answer to this question.

Thanks in advance!!!