I was diving Monterey with the DUI 300S with a expedition weight base layer shirt underneath. I was still getting cold for either long or inactive dives, but then switched my gloves to drygloves which made a LOT of difference.
If you get cold, try better hoods and gloves first. That may fix the problem.
Now that said, I recently purchased a DUI 400g Thinsulate. While it does diminish mobility a little (I tried on the 300s after using the 400g a while and was surprised how free I felt) you can't beat the warmth. For the first time I stay warm for any length of dive in Monterey, whatever I am doing. Heck, I could probably sit on the bottom motionless for two hours and still be warm. OTOH in the Summer I probably lose a gallon of water just walking to the water from the parking lot.
If you get cold, try better hoods and gloves first. That may fix the problem.
Now that said, I recently purchased a DUI 400g Thinsulate. While it does diminish mobility a little (I tried on the 300s after using the 400g a while and was surprised how free I felt) you can't beat the warmth. For the first time I stay warm for any length of dive in Monterey, whatever I am doing. Heck, I could probably sit on the bottom motionless for two hours and still be warm. OTOH in the Summer I probably lose a gallon of water just walking to the water from the parking lot.