In addition to all the aforementioned clobber, I would suggest that you consider also taking a small AIS receiver and a hand-held marine VHF transceiver.
All ships keep a listening watch on Channel 16 and you can see the location and identities of all ships within VHF range on the AIS display. From FL100, for example, you'll 'see' all ships within a hundred mile radius and more.
In the event of a ditching, your best chance of being recovered alive is if you have already alerted a ship before actually ditching. You'll have several miles of glide before turning onto your ditching heading and by closing the distance between you and your salvation you significantly improve your chances of post-ditching survival. You will also have triggered them to turn towards your probable ditching location instead of steaming away at 20 knots. Give them your current position, heading and speed and TTG to touchdown and let them do the chartwork to work out their best intercept heading. They will also do all the comms stuff with the rescue authorities ashore. Prefix your callsign with the word "aircraft" or they might not understand who/what you are at first. They expect to hear ships on that frequency. Aircraft are rare there.
You might even consider, if you have a sufficient surplus fuel reserve, applying a few minor jinks in your track to optimise your track in terms of intercommunication range with AIS-observed ships to give yourself a little bit of comfort factor.
For those unfamiliar with AIS: it's a little bit like Mode-S, but is transmitted blind every few seconds without interrogation, on marine VHF. The data string includes Lat/Long, ID course, speed and a few other bits of techno-wibble.