Looks like it should be a fun build, always nice to see something different.
I grabbed a curved needle set from Walmart a while back for a couple of bucks that works great on upholstery. I didn't even use the biggest one in the set and had no issues. For the thread, I used some sewing 'cord' passed down from generations... don't really know how long that thread/cord has been around, but it was the cats meow and stronger than some fishing line.
IS300 - 2JZ-GTE, DIY custom sequential 31psi at 2800rpms, yeehaw.