Nice start. The place where you have the car to work on looks HUGE!! Plenty of room is always such a bonus.
Hate to burst your bubble, but those "AP 4 pot racing brake calipers" look suspiciously like standard Austin Princess front calipers. It was a semi popular upgrade "back in the day", and a cheap ( if heavy ) way to get 4 piston calipers with bigger pads. I have a set of these calipers on my MGB, and I made a spacer to go between the caliper halves so they fit over the Nissan Skyline ventilated discs I have on the front.