Reassembling a two plate Timex movement is a pretty close definition of obsession; the words determination and persistence just don't quite describe what it takes.
I finally got a disassembled #21 movement from my Sportster back between the plates, but, like you, mangled the hairspring at the last minute. This movement was unlike the other Timex movements because it does not have a canon pinion, but rather features a friction fit gear on the minute pinion to allow setting. Probable zero chance that I will find a matching balance anywhere. The #29s is fairly common, and replacing the balance should be relatively easy compared to getting the plates together.