All,
After some preliminary model rocket tests, I'm dropping the SD Card in favor of your EEPROM shield.
The reason is that the SD Card can't seem to handle vibration or shock in a model rocket application, while (I assume) the EEPROM shield will (I haven't tried it yet).
While the memory size of the EEPROM is far less than the SD Card, the demanding need is for reliable data storage, which I hope the EEPROM will provide.
I'll get back to the SD Card for other applications, so thanks for all your advice and suggestions about this device!
-john