Bodain,
You bike looks great!
I don't think I have the skill or patience to do that!
One of the things I like about this hobby is the fact that I am the chief engineer, designer, idea steeler, president, vice president, laborer..... I work in IT to earn real money and in such a job I have to answer to people above me.
In my garage I answer to no one. I am free to explore any possibility. I am free to tamper with things I know abolutely nothing about...
Lacing spoke wheels.... Tried it. had some failures. Now it's pretty much a piece of cake.
Painting.... Countless failures. Every failure reveals additional experience for the next time.
Complete seat restoration... I do fiberglass very freqently now. I still don't do upolstery...
Shade tree mechanic... I have no problem jumping into any engine. I may even screw it up, but I learned something from that experience.
So now when I pick up another none running bike it's just routine. It will run very shortly.
Point is... Just jump in and do it. You can....
Creating your own seat from the stock seat pan or creating a total new one from a fiberglass experince is a very rewarding venture...