Here is the word from Wavecor.
Hello Glenn,
Thank you for your interest.
We generally do not run tweeter power tests without high pass filtering. So I cannot tell you exactly how much power can be dissipated directly at the voice coil.
However, it is bound to be in the 5-10W range, probably closer to 5.
If the drive signal is sufficiently low it will be possible to use the TW030WA11 to 1 kHz. However, we have no experience at all with such low crossover frequencies so I am afraid it will be at your own risk to try it.
Sincerely
Ed, Wavecor