Finally! Approximately 77.3 nanoseconds after my neighbor J called and told me my Taurus parts had arrived, I slid into his yard, collected them, and was back at the desk and feverishly tearing off the sideplate.
Popped in the new mainspring. (I will write this as if it really were that casual, ignoring the fact that I’ve never done it before, had no vise to hold the damn frame still, and had to remove Zoe from the desk 43 times during the process because her Kitten Sensetm informed her that there were loose screws to be biffed and scattered.) Slapped on the new grips. Loaded the pistol with five reloads with rock-hard primers.
Grabbed my ears, ran outside and fired it five times double action at an otherwise inoffensive rock on the ridge. Five bangs! Pistol is fixed!
The new grips are a big help, too. Now I need to find it a decent holster.