I don't know if you have any interest in doing this with yours, but I drilled a self taping sheet metal screw into the pan right under the filler tube, so I take out the screw to drain the fluid and not make a mess.
While the pan is off just clean the area on the inside of the pan, put the threaded screw back in and a little RTV around the screw shaft and she's ready to go back on.
Some trans shops drill a hole in the pan and put a pop rivit in it when it goes back on.
Next time they just shear the rivit head off and punch the rest into the pan to drain it and repeat the process.