Soil is the biggest factor in water lateral movement. Test your soil for how long and to what distance water travels in your soil. Plants need different amount of water for varying stages of growth. It all depends on the size of the root system that the plant develops. There are rules of thumb(green)that pertain to the amount of water per plant. You can find this researching the plant forums. Find the rate of flow of your emitters and decide if you want fast or slow water delivery. Add all the emitters you plan to use and add 20% and you have the flow rate of your mainline system. Flow rate depends on pressure and drip system laterals usually are 25-30 psi. Your main line pressure will 50-60 psi and pressure reducers will drop it to 25-30 for drip. Check the drip line pressure psi ratings to be sure. JMHO Aloha

I use RowDrip tapes from John Deere. They connect to 10 psi regualtors and give an even drip pattern. Emitters are pre-made in the tape and have from 8" to 12" between drippers. Flow rates are low, allowing water to seep in rather than run off. The parts are cheap, and the tape is 4 cents/foot (but you need to buy a whole 1,400' roll). For best results, put a layer of mulch over the tape; this protects the tape and prevents evaporation. I illustrate the system on the page below.