I have the escapement put back together. I still need to assemble the keyless works (the mechanism that switches the winding stem from winging mode to time setting mode) and the motion works (the mechanism that moves the hands). I had a tiny screw fly away last night, and cannot find the damned thing so I had to order a replacement. Can't finish putting it together till that arrives.
I decided to wind up the movement and put it on the timegrapher, just to see how its changed from before I began working on it. Before I took it apart, the watch was losing about 5 minutes a day, had a beat error of around 5ms, and the amplitude was only 115 or 125, I can't remember for sure (forgot to write it down). Ideally beat error should be less than 1ms and amplitude should be higher than 250.
Here are the results, after I disassembled the movement, cleaned it, relubricated it with the proper lubricants (three types of oil and one type of grease) in the correct places, and reassembled it:

Now, instead of running too slow by 5 minutes a day, it is running too fast by about 4 minutes a day. Amplitude is a very, very nice 305; and beat error is down to 2.4ms.
I thought the movement might have become magnetized, which can cause a watch to run several minutes a day fast; so after looking at the results shown in the photo above, I demagnetized it. It made no difference; so I suspect the man who 'repaired' it for me before did not do anything to the watch but move the regulator to make it run faster. That didn't fix it because it needed CLEANED, which I am certain he did not do. When I was disassembling the movement, it was full of dirt and lint. The jewels looked dirty, too. I could see dried gunk in them when I held them up to a light and looked at them through a loupe.
I cleaned it properly and replaced the mainspring and look at the result: good amplitude and now it runs fast. I can correct that when I regulate it later. I have to wait a few days for my new screw to arrive, so I am going to let the escapement run while I wait in order to let it settle in with the new lubricants. After I assemble the rest of the movement, I will then regulate it. I am confident I will be able to get it keeping accurate time to within a few seconds a day.