Help the basketball ref with the balk rule

[KCOfficial]

First off, I respect the baseball umps so much that I don't want your job. I'll stick with basketball.

I know balks are a never ending question. However, I tried searching many resources to find the accurate interpretation of what is as described in rule 8.01(b)

Specifically, at a junior high level game. Runner on first. Left handed pitcher from the set position (hands at belt level), goes into his motion. Lifts his right leg and holds it in a balanced postion for 1-2 seconds (hands at chest level, no break). Then, makes his choice of home or first. He picked off 3 kids in a row.

Is that legal? is there a time limit that he can keep his leg up? or does it have to be one continuous motion either home or to 1st? Do the hands have anything to do with the call since they went from set at the belt to set again at the chest.

I hope I explained it correctly. thanks for your input.