Been using scuba pro hooded vest with their 3mm wetsuit during the winter months in the Middle East, just as good as a 5mm set and can easily go well over an hour in the water. I do prefer the vest under the wetsuit though. I find the extra tightness helps restrict water entering the suit. But I have a buddy who is the opposite way around so that bit you will have to try for yourselfSearched for a current thread on this, but didn't find one. I'm Looking into a hooded vest in the 5mm range and there are a number of contenders. Scubapro, Pinnacle, Henderson, Bare all have an offering. Any preferences out there?