Got the new vent installed this past weekend, works well. Found out that the roof membrane is a lot thinner than I thought.
Measured out around 15 mils!
I am getting a sheet of PVC membrane from work, it will be 36 mil... minimum, might see if we have any 45 mil stuff laying around.
Only down side to the new vent is that it makes the bathroom a lot darker, it doesn't let daylight in. Other than that it works great, we are camping right now and it has been pouring rain, we can run the vent and nothing gets in.
Aaron