I have a DUI TLS350 suit and have done about 20 dives with it. I have taken the Nauii drysuit course and haven't experienced any problems operating the suit. I use just a little air to take the squeeze off and then use my BC for buoyancy control. I also dive with the dump valve opened all the way as is suggested by the DUI manual. I have noted that others play with their valve a bit more. What is the adavntage of diving with the valve partly closed. I know the suit will hold more air with the valve closed a bit but why should one change the preset pressure differential setting on the valve? Thanks for your input.