BillyBob, thats a lot of cerebral candy to consume.
It throws up a lot of questions.
Forgive me if i wobble on.You probably considered all this years ago.
below, though its probably the wrong terminology, i will use the expression 'dew-point'to indicate the point when vapor condenses.
Many of the people I've dived with, came out wet. Sometimes it was through leakage, but other peoples t.shirts looked exactly like they had just been for a run. I totally agree about the 'moisture shut off switch' I think it works better/worse in different parts of the body.
e.g. I think hands are much better at regulating themselves than feet.
considering the drysuit.... we have body, fleece, VBL(drysuit), then cold water. Even though the water is cold, there is not a big enough temperature change to induce the vapor to condense.
thought...the VBL micro-climate only works if you seperate it from the dew-point by using warm insulation. So, if we had no top quilt, then the warm vbl would be in direct contact with the cold air, causing an immediate dew-point, condensing the vapor to water, and collapsing the micro-climate.
With a cold drink on a warm day, we get condensation of moisture from the warm air on the outside of the can/bottle.
tin foil wrapped around an ice-cube in a warm room will collect moisture on the outside. I believe this is not from the melting ice-cube, but from the moisture in the warm air condensing at the dew-point on the foil. If we put insulation between the ice and the tin foil, there will be no condensation on the tin foil.
I would venture to say that wearing a VBL at room temperature should not cause wetness, unless you overheat, as there is no dew-point to condense the vapor inside into water.