Megan - they are standard size trees. But there is a whole lot more to the story. The dwarfing root stocks on citrus don't like the desert soil making them harder to grow. Our program only brings in the types of trees and root stocks that will thrive in our area. So we have an education program that teaches to keep the trees small so they are easier to pick and this is done through pruning. It is actually very easy through pruning to keep the trees small.
Spacing depends on what you are wanting. If you want a hedge fence then 6 feet apart makes a great one. If you want stand alone trees then 10 to 12 feet apart is good.
I highly encourage you to sign up for our classes this fall where we teach all of this for free at FruitTrees.org.
Also don't miss this - https://urbanfarm.lpages.co/ftp-launch-2022/