The helmet looks like a graft, so try a grafted blintzed frog base? I don't know what the proportions of the graft are, but it's definitely some kind of blintzed frog base. The legs look to be equal length and from the same point, but it's hard to tell the structure without more angles.
So my best advice would be to experiment with a blintzed frog base and try to get the helmet first. Of course, you could always try to contact Brian and ask him if he has any design notes.