This:
is what I started with last fall. It's still got the points/coils/condenser ignition in it. I statically timed it on my workbench in the basement last week - It runs like it's right on the money!
I used a combination of ebay, Rask Cycle (near Pittsburgh) and British Only (near Detroit) for tools and parts. There's a place local to me that I got a few parts for also - BCF Cycle in Kirtland, Ohio. A few tools were indispensable - like the tool to get the crankshaft pinion off and the camshaft pinion tools. Other than that, I just used what I had in my toolbox already, for the most part.
Thank goodness they had gone to SAE sizes by '72, my '68 BSA drives me up the wall with the Whitworth bolt/nut sizes.
I got the 4 Aces dvd also - he had some good pointers - not many gotcha's applied to the '72, though. I wish the dvd had more pointers about timing, and setting up the clutch, than it did.
... Oh! and I put on an Rocket-3-type oil filter - it's that shiny aluminum cap, just below the right airbox in the first photo. It's a tube that mounts vertically. It's machined so the input line goes in the bottom of the tube, then the return line comes out the side and points right at the return fitting on the frame. It added about a pint to the oil supply, too!