There is a function "blecm_connectionEventNotifiationEnable" originally called in "wiced_sense_connection_up" (not the right place, but OK). It seems to have a timer value as parameter, "default_period". It seems to be related with which delay the FW checks for next Notification needed to be sent. You can modify here as one place.
When Notification has to be sent, in "wiced_sense_tx_opportunity_notice" there are SW counters: FW counts per SW how often the need for Notification was there, via "wiced_sense_polls_since_last_hpt": almost all events (fast) are for AGM sensors (fast speed on Accel., Gyro and Compass), some in "between" are for HPT sensors (Hum., Pressure, Temp.). You can change the SW counters here as well. BTW: this SW counter determines the speed even more, like a divider on a real timer.