I thought you said you have a junk rear cover? The idea is to machine a rear cover so it is flat on both sides and taking the outer edge off turns the bearing pockets into bearing holes. If this is done carefully enough I think you end up with a shimming plate tool. Add to this a couple of parallels and you are set.
So all you need is a junk rear cover and I think you have machinist there?
Never memorize something you can look up.