In the class I was in we were taught to point to the ground on a dropped third strike, point to the spot where the batter was hit and to point fair or foul on close balls down the line.
I was taught many many years ago that if you point with your right hand, then you are signaling an out of a strike.
__________________
Charles Johnson Jr
NFHS Class #1 softball/baseball
ASA/USSSA
Dayton, Ohio
I have been umpiring so long that it was called Rounders when I started.