This time last year I started looking into the same thing. I was looking for the top and bottom combo to save some coin, and for my wife to be able to wizz easy.
I purchased Bomber Gear tops and bottoms for the wife.
After rolling the two together as perfectly as possible, and purging out any extra air, they are mostly dry. After about a minute of drifting behind the boat the combo leaked about a cup of water. If you take a swim, you'll get a little wet. You better have something dry to change into if its real cold.
I'll get the mrs's a nice Kokatat goretex one of these days, but she's happy to wear the 2 piece setup for now.