Well.
I never in my wildest dreams have expected a "remarkable" from ANY experienced bike modder! Thanks man!
The stitching was done by hand, but I only had to switch one seam, the one that goes up and over the hump on the front edge. I've never sewn a thing before, and I knew it wasn't going to be neat so I made it a hidden seam, tucked away inside out. Then I glued the whole thing down so there wasn't any stress on my stitching!
The other seams were already there on the cushion in the original design.
I pushed some wire through the tank outlets, but it's such a tiny filler hole, you can't see where they come out, and I couldn't tell what was going on by touch. I'll stick a bit of fuel in and see if it comes out of just one outlet, that should tell me something, (although I'm not entirely sure what!
Here's a pic of the seat unit mounted...
