Patagonia Houdini as vapor barrier

I'm doing a 2-day bike ride in bitterly cold winter conditions soon and was curious if anyone has used the Houdini as a vapor barrier, and if so what the results were.

Tomorrow the temps are going to be a balmy 30 degrees Fahrenheit, so I may not have the chance to test in "real" conditions (about 0 degrees F) beforehand.

I was thinking of having thin polypropylene under the Houdini, then an insulated soft shell.

Maybe try asking here bikepacking.net/forum/index…

Not really what you asked, but would a true vapor barrier be a good thing during an intense aerobic activity? The only time I used a vapor barrier was inside a sleeping bag, and while it did keep me warm in that situation, I was pretty much soaking wet by morning, and that was after just lying there asleep!

I'm not trying to be a wise guy, just wondering...