Sorry for the short answer, i was in the metro.
Now i'm in front of my computer and i can answer more accurately.
The length of the waves are limited to 512 (that's because of arithmetic limitations of the anti aliasing algorithm).
A wave should represent a cycle of a waveform.
The number of waves can go up to 1024.
Many instances of the load object can be used but the total SDRAM used cannot go beyond 1 mega samples.