Auto Mode- Change The Initial Spool Up / Take Off Speed

Hello, I have looked all over for an answer to this but haven’t found anything yet…

My question pertains to a fully auto mission. Flying a big hexacopter (about 55lbs) and what I’m finding is that as soon as I initiate a mission on the ground (aircraft is on the ground, motors not even spinning), the motors spool up quite fast and the aircraft launches off of the ground quite fast. It then goes into a nice stable vertical climb.

So my question is not how to slow down the climb rate, which I assume would be (WPNAV_SPEED_UP), my question is how do I slow down the initial takeoff speed itself? Any way to slow down this initial acceleration into flight? The actual climb rate itself is perfect and I don’t want to adjust that.

Running the latest Hex Copter firmware with a 2.1 Cube.

Thank you!