Trevor, Quite a few years ago John Fielding (our forum member) gave me a few seeds which he had brought from Vai in Crete. They germinated well, and rooted out very quickly. I had sown the seeds individually in 3-inch pots. By the time I was able to plant them out in Greece, the leading roots of the two plants I took had curled round, but I found it fairly easy to tease them out and more or less straighten them, and the young plants took off well. Years later they are still thriving and seem very solidly settled.
If I were trying them again from seed, I would I think sow directly into a one- or two-litre deep pot, the "root-training" type with ridged sides and a mesh instead of a solid base, and plant them out as soon as roots reached the base. But perhaps that's a counsel of perfection. Judging by my experience they little plants are so tough and so flexible that they will put up with almost anything!
Beware, they will take revenge on you as they grow up. The stipules along the lower part of each frond are incredibly vicious!