stm.latestNumber seems to be the right direction to go.
But for the pause, if I use Append(), I seem not being able to use the Fade (or others) read out effects;
if I change the readDelay parameter to achieve pause, I need to call stm.Read() or stm.Rebuild() each time I change the STM setting by script, and the stm will read from the start again. This happens even I checked stm.rememberReadPosition. What else can I try?