Well, that's the layout I went with!
Seeing as nothing has arrived yet (binding posts, voltmeters, transistors, resistors, shunt resistors, knobs, pots, etc?) I'm using ebay specs for the cutouts... and hoping they're right!


The bottom row of binding posts line up with the lip on the aluminium plate, so they will be grounded straight to that... no stuffing around with terminals and links

(hence the drilling holes with the case half assembled, so they line up properly)
Oh, and I bought a crusty, cheap(ish) second hand drill press.