The version of AC which I am using a is older, so you will need to adapt the settings, appropriately, for the newer version.
The best thing you can do is experiment by taking off the propellers and changing the values of MOT_SPIN_MIN, then see which value works best for you.
What you are aiming to do is have the lowest safe motor propeller spin (when you arm the copter). But if you make it too low, the props won't all spin up and maybe when you arm the copter, the motors will not spin.
You can do all the tests, indoors, without propellers and it shouldn't take you more than 30 minutes to find a setting that works well for you.