Heard back from Tony McDonald, the Rope/Cordage Manager at Donaghys. His response:
...We have tested all the splices and for an e2e a slightly modified Class I is the answer. The tails are just a little bit longer to help with the splice. We will have this published over the next 2-3 weeks...
Highscale, you were on the right track! I'm looking forward to seeing the exact measurements they call for...but it looks like we (almost) have the answer.
love
nick