Well, this is embarrassing. Now the alsamixer settings save and restore. Since I tried it last I installed flaxpdf.tcz, gpicview.tcz, as well as evince.tcz (but deleted it later).
gpicview.tcz had a missing library error (libGLESv2) which I was going to report. Installing the libGLESv2.tcz extension fixed it, but probably a .dev file needs to be corrected.
Now I'm wondering if alsa (or alsa-config) might have a library issue too that one of the installs inadvertently corrected.
Sheesh.
thane