Transient settings are explained in the manual:
https://invent-labs.com/ems/docs/en/settings/injection/transients.html#enrichmentenleanment-settings
First, you have to make sure that VE map is tuned well in the range of your interest, e.g. in the cells, that marker is going through, while pressing the pedal. Without this, you can't adjust transients.
Then, watch for a wideband response, and adjust settings accordingly. According to your description, you want to minimize mixture dip by increasing Enrichment Fast Level.