I've never had to egg out the holes. When you replace one side, loosen the bolts on the other side as well. use a hoist to lift the motor a bit, bolt the new mount to the motor, then run the bolts through the holes (use longer bolts to do this if you want, then replace with the right bolts later) when all 4 bolts (both sides) are lined up in ther holes, lower the motor down. This forces the bolts to act as a guide, and lines up the holes for you.
BTW, I have rockstomper motor mounts. I have had very little problems getting them lined up
