I finally discovered what I was doing wrong with my tsa-tsas.
1. I wasn't letting the mold release dry
2. I was overworking the clay
3. I didn't put in enough clay to form a good stamp.
After over an hour of sweating and grumbling as to why it wasn't working, I asked Chenrezig and as I sat back in a heros pose and rested my back the answers came to me.
So I made corrections and the tsa tsa popped out nicely. Not perfect--yet--but by next week's practice I should have it down. Eventually I intend to teach others how to do it. But for now, I am my most onery student.
As my biology professor once said, "if all else fails, read the instructions."