I would put that slider back where it was. To adjust the gyro, you need to do it in the Tx. There are two different ways that you adjust it depending on your setup.
1) Using a separate Rx such as the AR7200
If you are using a separate Rx, then go into your gyro menu and set the channel to 5/Gear. This should be the default setting when you make the model.
2) Using Dual Satellites Directly Off The 3GX
If you are ONLY using satellite Rx's off the 3GX, then go into your gyro menu on your Tx and set the channel to Aux2 or channel 7.
Once you are done setting the proper channel, you need to set your gains. On the DX7s/DX8 a good starting place is 35%. I set mine as follows...
Switch position
0- +35%
1- -35%
2- set this to 0, meaning no gyro
The reason I do that is because right before I fly, I can flip the switch from position 0 to position1 and back to center the tail blades. Start with 35%. Fly the helicopter as you normally would. If the tail is not locked in, raise the value (heading hold only, never fly in rate mode. Heading hold is above 0, Rate is below zero). If the tail is wagging quickly, then lower the value.
Hope this helps.