Terran strategy: Cliff drop around the clock

Terran tank drop on the cliff and behind the minerals has been a superb tactics againts your opponents in Big Game Hunters. Drops are often seen on 11, 9, 6, and 5 as they could be easily executed. But what about 1 and 7?

Dropping tanks on 1 and 7 cliffs can be extremly difficult and not many has successful did it, including myself.

If anyone know this trick, please posts in the comments and share with us on how you do it.