I got a pair of the Rapa Nui Hokas for exactly the same reason (metatarsalgia for over 6 months) . I wore them for the first 70 miles of the Hardmoors 110 and they were fine, but I fancied a change of socks & shoes so changed into my usual Speedcross. I next wore the Hokas again on the L100 this year but despite the extra cushioning (and painkillers) I had metatarsal problems again and was forced to retire at Dalemain (which was a real bummer because I felt pretty good otherwise). I do tend to go over on my ankle a bit more than usual in them, and noticed today that a hole has developed in one of the uppers which I wouldn't normally expect after less than 200 miles.
Conwild - have you still got problems with your feet? Any advice would be appreciated