hey sabbot!
I've just finished my (first) diff rebuild. It's not in the car yet, so I cannot say at this point if I`ve been successful. But I could send you some helpful video links that explain some things in general, not particularly for the ford english diff, but that doesn't matter at least for a few things. You should at least have the tool to measure the "cap spread" as mentioned in the book or have the ability to produce one, nothing really complicated. All you need are two dial indicators and some metal. Then, if you want to change pinion and crownwheel you should be able to calculate the pinion height. There are general toolsets available to do that. I haven't used them, cause I did not change the crownwheel or pinion, but I've found a youtube video that explains how to calculate and use them. Without that pinion height measurement tool you may take the diff apart several times before you get it right. Let me know, if you´d be interested.
https://www.youtube.com/watch?v=S61Ut8tOu1ocheers
Matthias