francophile 

While I was recovering I made a couple of trips to the shop to sort through parts, rearrange and try getting my hands on some wrenches, loosen up the joints.

In the process, I came across a seat I took off an old 70s beater a couple years back. Didn't pay much attention then, other than "there's an at-home hack". This time I looked a little more closely.

Someone put a lot of thought and effort into this for a home job! Took a plastic seat. Cut a window into it. Drilled holes on the short sides of the window and drew springs across it.

Looks like they made some custom steel plates for underneath and (re?)purposed some hangers, then re-skinned and screwed it all together.

easyupbug 

Wow, I just hope he liked the ride, does it look like the saddle leather was well used or not, a success or not so much?

francophile 

It definitely had a little wear on it. I will say this: It's one of the softest seats I've ever put my ass on. You could have an army of hemorrhoids plaguing you and I think the seat would've been comfortable. It looks bobo as can be, but something tells me this was more of a function-over-form homemade product.