The Maya had a form of agriculture that was basically a transitioning forest. They had a number of different plots at various stages of growth from annual crops to mature forest.
They would first burn the land to clear it and put some of the scrub/brush back into the soil. Then they would plant the tree species that would eventually become a mature forest, along with their corn, squash, peppers, herbs, and everything else. They would harvest the annual crops for a couple years until the perennials crowded out the annuals. Then production would shift to tree fruits. Eventually the fruit trees would become timber. They would have enough plots in production that there was always a bit of each product, annuals, perennials and timber. This system mimics a forest and provides excellent habitat for a wide variety of animals.
For you, an alley design might provide more harvest efficiency, and you can see examples of that in the Gotsch agenda and Life in Syntropy. It works, but it's not as profitable initially as conventional agriculture which maximizes yield per square foot per season.
The row width and planting density is depending on how soon you want the tree canopy to shade out your crops. Closer plantings = fewer seasons of annuals. But you can always thin your trees later to open up more light.
Just remember to return the cut wood/brush/weeds to the soil to feed soil biology and add organic matter.