You don't use a 2nd stage reg with a dry suit?
Some dry suit divers use a small separate tank to inflate their suits, with just a first stage and an LP hose. This tank can contain Argon, which you can't breathe but which has better thermal insulating properties than air. It also has much better insulating properties than Helium, so that's an option if you are diving trimix instead of using your back gas to inflate your dry suit.