WOW, like already said: "That's a lot of work!"
I've restored three ST1300s and I'm still working on my forth, which entailed more, since I did an engine swap.
It seems that the bikes in Europe get a lot dirtier than the ones I've dealt with. Just the condition of yours, when you got it, blew my mind!
This one was used only and just ONLY in city environment, they could be in any condition. This is the worst I've seen too.