You might look into micro sprayers that may be what your wanting or could use.
They will put out the diameter you want.
I have used them before too.
One other thing you will want o go to with what they call head to head coverage for most things to get a full coverage.
This means you will still have to go to the heads being around ten feet apart or you will end up with dry spots.
I put my yard sprinklers in with head to head coverage.
With a mist system the stuff just sort of floats around before it hits the plants depending on how high up the heads are.
The water mist I used for fire protection was running off 2000 PSI air tanks.
http://www.sprinklerwarehouse.com/Mi...ers-s/7841.htm