Take the boat for a test and to get a hands-on feel of how the boat handles different conditions. It's not really useful to test in 'perfect' weather conditions as you will not always have 'perfect' conditions when boating/fishing. I dont have personal experience with the Eclipse 7600 so i'm unable to give specifc comments, but I would take a comment regarding tunnel shape I saw on another forum with a touch of salt.
Ride quality, stability and 'broaching' are all related to the hydro-dynamics of the hull. With cat hulls the design of the sponsons influences how the craft handles but is not the only factor. Top heavy boats and/or boats with poor weight distribution, or badly trimmed for that matter, will perform badly regardless of hull design. The tunnel should be above the water when the boat is on the plane so it will have less effect on the ride than the sponson design. When cat hulls 'ride'onn the tunnel the boat will pound/bang when running into the sea as the water in the tunnel compresses and has nowhere to escape.
