I've been working on the seat and mounting things as quickly as possible while I have time. Here's some progress.
My seat consists of two parts: the seat pan, which is two pieces of bendy plywood laminated together and the cushion which is another piece of stiff plywood with gel and closed cell foam. The cushion will be covered with some suede and stitched up all purty. The seat pan will also get a walnut veneer once I've created all the mounting holes and what not.
Laminating the seat pan (you can never have too many clamps):
One thing thing I realized after I popped the pan out, the metal pan below buckled quite a bit during the powdercoat process and those buckles transferred to the wooden pan. It's not a huge deal but I'd definitely do this differently next time:
Underside of the pan, showing the threaded inserts I'll be using to attach the pan to the metal of the frame below:
Mounting holes:
Cushion. It won't sit this high as some of the fabric will be tucked under to make sure it's nice and taught around the stiff plywood base. Still trying to solve exactly how this will be attached to the pan but I have a few ideas.
More or less the final position of the cushion:
Underside of the cushion for those who are curious. I wanted to hide the small area where the original battery box mounted so the cushion has a small extension on it. That's why there's a section that's "enclosed".
Pretty happy with the look, I think it'll really pop once the walnut veneer is laminated. Stay tuned!