[Jim Porter]

After he comes to a complete stop and lifts his non-pivot foot to begin his motion, it doesn't matter much what he does with his hands as long as he doesn't separate them except to either deliver the pitch or throw to a base.

With a left-handed pitcher throwing to first base, you should be more concerned about what he does with his free foot than his hands. Make sure his free foot doesn't swing beyond the back edge of the rubber before he throws to first, make sure he gains distance and direction in making a step before throwing to first, and make sure he steps more towards first than home before throwing to first.