I think you have explained the process very well, Daniel - Well done mate 

Here's a trick I picked up along the way;

Normally, the switches are taken off the rear of the drop target assembly. so when you test the mechanical side of the rebuild - it works fine.
Before screwing the switches on - clean them with a business card and make sure they are gapped correctly. Check that the heavier switch blade (that makes contact with the guitar!) is clean and what you can do is polish it with a bit of brasso, and also the edge of the "guitar".

Now test the drop target assembly with the switches in place and make sure they drop correctly. Make any adjustments now - before you install.

Second point - Notice the brackets on the Drop targets are elongated. This means you can adjust the positioning of the targets. Too fat back will cause the drop target to "bounce" off the rubber behind it" - Too far forward will cause friction with the front face of the target. Rule of thumb - Visually check the targets (in dropped position), and make sure that they are all parallel with the cavity in the playfield. In the UP position - make sure they are not touching the playfield directly in front of them

Third point - If you are installing new (genuine hot stamped) target that are Red on White, or White on Red - cover them with mylar. This is because the law changed in the USA and you cannot use lead in the manufacture of Red paints. So they will chip. I mylar ALL target anyway !'