Looks like a good plan, except for the tires. I would go with some race compound Avons, Continentals or Heidenau. I think the Pirelli Sport Demons, Bridgestone BT45 and the Dunlop GT501, just don't offer enough grip for hard racing use. I run the Avon AM22 front in a 110-18 and the AM23 rear in the 130/65 vb 18. It is a special race profile 130 designed to work ok on a narrower rim.
I also think that bike will fit in V4 and clubman and be competitive, you can run 17" wheels in those classes. When I had my Ascot set up for V2 I had an extra set of 17" wheels I could swap ouy for V4 and Clubman. Especially since the vintage classes run on Saturday and Clubman and DSB run on Sunday.