I finished an Arctic Tern 14 about a month ago. I ordered the bulkheads form pygmy and installed them before I put the deck on. It was easy and worked fine. I didn't order their hatches, but instead just cut hatches out of the finished deck, epoxied on some hatch lips (with spacers) and attached the hatches with bungies running through the bulkheads to cleats in the cockpit. Sort of my own variation on the methods that have been so well covered on this board. But I can't see any reason not to use the factory bulkheads.

Godd luck - you'll enjoy building it.