Rule question regarding sprinkler system

You can't assume that the ball would have rolled down the hill, no matter how certain you might be.  You were entitled to relief from the immovable obstruction (the sprinkler head).

The proper procedure was to determine the nearest point to where the ball lay which was not closer to the hole and gave complete relief from the obstruction for lie, stance and area of intended swing.  From that reference point you get a one clublength arc not closer to the hole in which to drop the ball.  If the ball, when dropped, rolls closer to the hole than the NPR, or rolls back in to a position of interference, or rolls more than 2 clublengths from where it first hit the gound, then it must be redropped.  If it again rolls into one of those positions, then the ball must be placed on the spot where it first hit the ground when dropped the second time.  The ball may be cleaned under this rule, but a ball may not be substituted for the original ball unless the original ball is not immediately recoverable.

Sometimes the rules help.......sometimes. :-D

Let's assume that the ball is in the middle of the sprinkler cover and i could find the NPR to the right or left. But if i choose to drop to the left, the ball would surely roll to the bottom of the hill. Twice this and i place the ball, to my advantage, in a nice lie.  But choose the right side and it's undesirable hard pan.

May i choose which side to drop?

If you have a situation with more than one NPR then yes, may choose which one to use. Equidistant NPR's do not happen very often.

Remember too, you must have complete relief for lie, stance, and swing. With very few exceptions, the NPR is one single point on the course.

You must place the ball where it hit the ground when you dropped. You can't place it where you choose.

But i can drop, with some restrictions, about where i like. Right? I get the one club length from the NPR, not nearer the hole. So i can move the club in a semi-circular path around that one NPR point, make my choice and drop. As long i continue to obtain complete relief from the place i choose.

Correct.

Indeed. But dropping from shoulder height can you guarantee to hit an exact spot rather than within 6" say?

I'm only 3 feet tall  !!