I am building the InMoov Robot When I tried to install the servos I found the Simple Server Bed was not deep. Then design a whole new servo bed part I made those spacers to use with the one. I also included a large one for the areas that have more room although you can use all ones that are small. Some places the smaller one will work. Position so the square holes are over the screw holes. You will also need wood screws. I am using #6 5/8"
I also included in case you need to modify, the 123d layout files. One for the Simple Servo Bed could have made things a lot easier