Hi, does your aircraft not have quick release pins for the canopy? Our Robin DR400 has a couple, you can then jettison the canopy prior to ditching at lowest possible airspeed, stall warner blaring, parallel to swell so the nose leg doesn't hit a large oncoming wave head on, which would not help matters.
Keep a look out for boats there will probably be more than you think and aim for one once gliding.
Not sure on your situation but probably more trouble than it's worth to try and egress with a parachute i.e. get it wrong and you may hit the tail/prop/wing etc. Get the ditching right and the low wing configuration may even float, so you can eat your sandwiches whilst waiting for International Rescue.
Seriously, give thought to an immersion suit, it's the cold and hypothermia that is the real killer. There are numerous long threads on this topic both here and on the Flyer forum.
Cheers