Once again, I have to comment. You will rarely face the same chip twice. So unless you are working on a new shot, why hit 20 balls from the same spot to the same hole? Get your feal randomly, get to understand that each and every shot matters, and treat each practice shot like a real one.
I don't know if this helps too much, but when I help coach, one thing I love to do at the very end of practice is we have a competition. With around 10 kids(boys and girls), I make all of them chip from one spot to one hole. Usually pretty easy. The closest 4 move on. Then a bit more difficult shot. Top 2 move on. Then one last chip, usually decently difficult. The winner gets a candy bar and soda, on me, and the 2nd place gets a soda or candy bar, their pick.
P.S. Actually usually it's a gatorade and granola bar, but most of the time I let them pick.
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