http://www.hummert.com/product-details/29215/tri-flo-spray-stick
This is the style I like; there are many options. The 160 degree type works and is a cheap option for large systems. I've built residential, commercial, nursery, and bonsai only systems. Hummert is just one supplier, so a few minutes of irrigation supplier searches will save you more for spray stakes or misters.
Great walk through above by Mark. The only thing I worry about are spray shadows from trunk(s) when using one sprayer. Moving the sprayer from time to time is often effective.
For most nursery stock plants, I used Netafim spray stakes as different colors are different gallons per hour. They are not adjustable.