This servo mounting adapter does not require that you to remove the back of the servo. There is some interaction between the lower servo mounting screws and the four holes to mount this to the next servo bracket. Some servos are too short for the back mod and some have a circuit board that makes the back modification not work. This gets around those issues. The screw for the 8 mm bearing should be a flat head 3 mm screw, You will need to taper the hole to match the screw head or use a soldering iron to make it fit better for larger servos.

Anycubic

All-metal Mega

Doesn't Matter

Doesn't Matter