If using the motor with the adapter plates at the top, like I have on my 1.2CM, you should really drill 2 holes, one each side, where I have indicated, in the picture below:
View attachment 49494
I have now done this with mine, as indicated in another thread, and the motor works perfectly, I even have it tracking the arc from 42E to 30W. I still need to make some fine adjustments, using the bracket, to increase the signal, but unfortunately the last day of dry weather I used to disasemble the dish, remove the motor, drill the holes and put everything back again, 5 minutes before the rain returned.
Eventually I will get round to fine tuning, to increase the signal quality on the weaker satellites, when we have a bit of sunshine, so probably August. At the moment my garden is under water, the way it's been since the end of May !!!!!!!!