I would replace "decent aeration of vapor" with "minimal to moderate diffusion of vapor through water."
In-line percs, circs (circular perc/UFO), 2-4 hole percs are all good examples.
If you're like most you'll want one chamber and a perc that doesn't have the most diffusion of the bubbles of vapor (these would be things like matrix percs, fritted discs, lots of honeycombs, etc). Unlike smoke that needs this to smooth the hit out, vapor only needs a little to condition the hit. This is subject to preference, of course. More diffusion also strips flavor, so that's the trade-off.