Subbing to watch the show and help out where I can.
In all honesty and experience, find a doner. Parts are really that hard to find. I just spent 2 years doing what you’re doing with a Transporter the Rescue. I got hung up on nut lugs and posts, ramps that were not supposed to be made, a never made again ship part... If it wasn’t for luck and some really great pin heads and friends it’s taken a decade to develop; it would still be in pieces all over my house and work office.
Taf is 3x the Machine mechanically that TTR is, I have no doubt it can be done, but I think your In for a longer project than you realize without the experience in parts and people than you may realize.
Still though, you’ve got gutz and experience !