choosing ADXL346 interrupt ??

Hi

I am using ADXL346 in my application.

I need it to interrupted when it sense in Z or Y axis   12g for more than 300mSec.

What interrupt should I use?  SINGLE_TAP or Activity or other?

What will append to the sensor when it will be 20g? What result will I get? Maximum? Will it be damaged?

Please advice

Regards

Yossi