Thanks CGR!

DrFrier, How can you tell? You can't.

My basic installation is to tighten down the screw until you see the grommet distort, then back it off a little so that it still contacts the grommet, but the distortion is either done, or diminished.

They don't need to be perfect, just tight enough so they don't move. I've even had times where the servo was in too difficult a spot to get all 4 screws in, so I left one out. Of course, I try to avoid that, but if it happens, I'm not going to lose any sleep over it.

PS, I rarely ever pre-drill