What amount of drop are you guys using for you ball mount with your hitch?

There is no one answer for this, it really depends on the trailer. I am using a 2 in drop.

I too am using a 2" drop for the trailer I have.

If you are pulling a trailer with tandam axles this is very important. You should select a drop that will have the trailer sitting level when connected with your normal load.

2" drop for a Big Tex 50LA 6.5' x 14' tandem utility trailer. The toybox uses a adjustable WD hitch.

If you are pulling a trailer with tandam axles this is very important. You should select a drop that will have the trailer sitting level when connected with your normal load.
Don't forget to make sure that your airbags on the rear are adjusted when measuring for drop. You will probably need the trailer hooked on and not sure if motor on or ignition turned on and/ or tow mode on to get the suspension adjusted and then measure how far off level your trailer is. That is your drop/raise.
I have afeeling scr83 or Cillyone one of the other towmasters know exaclty how all that works....