I have the dunlop K70s on my RYCA cafe bike. I love those tires.
My seat is going to be a traditional cafe style seat. I have a guy making one for me because I couldn't find a fiberglass one I liked. He is making mine out of sheet steel and hand forming it using an English wheel. Should be nice if he ever finishes it.
Now, my CB60 build on the other hand is going to have a tracker style seat like your Deus inspired picture above. I was hoping to put the sheng chin tires on that bike too, but will have to look elsewhere. We can still get the K70s in the USA but not in the smaller sizes needed for my build.
Good luck with your build- I will be following.