i do think this area of cleaning needs looking at.
a school of thought says that if you use fan jets, which normally run on a higher flow rate you may cause spotting,there are a few videos explaining this.(perry tait,jr racenstein)
if you use a pencil jet.normally a slower rate and cascade the water down you get less spotting,so the other theory goes.
i have for the last two weeks been varying in between and i have come to the conclusion i am more happy with a fan jet on a higher rate.
i feel i get more work done, i have not seen any increase in spotting, i may be wrong.
if you want to save water but use fan jets then gardiners low pressure fan jets are good,less water usage but still get a good "fan" effect