Testing at the dock... initial stability is decent but final stability is very high. So, you can lean it when you need to (broadside waves) but tipping it over would take real effort.
The cockpits are adequate but I would like them just a bit larger. If you are over 6' you'd really have to test this. As for spacing, you can bump paddles when you get way out or synch but this is rather unlikely. So, again, I could stand a bit more space but I'm OK with it. The seats are very comfortable with higher backs than the Passat.
We paddled this boat imediately after the Passat 22' double and it was so much more relaxed to sit in and paddle. Of course the Passat is faster but the Gemini is not slow at all. We thought it moved pretty well.
There were no waves to test it on but I think it would do well. The bow is very deep with a nice flare. Also, the fact that it has good final stability and yet the ability to lean it, says that it would rice waves well. The deep bow I think would also allow you to put a heavier ppaddler up front without sacrificing seaworthyness. This I really like because I get tired of sitting in the stern.
Overall, I think this is very nice double and we'd take it over the Passat even at the same price..... The Passat is gorgeous though.