Creating shady pecan canopy

Hello all!
I am planting a bunch of native pecan seedling in my backyard partly for nut production but more for creating shade for summer.

Resources on pecans seem focused on commercial growers and maximizing pecan production and want pecans 40 feet from any other tree.

My question is: how close can I plant pecans to each other and other trees if my focus is more on creating shade (slowly)?

There is already a central group of tall hackberry trees that appears nearing end of life that provides this shade, so I planned on adding pecan seedlings outside each of these to serve as their successors. I hoping the pecan trees do not die or grow severely distorted due to proximity.

Many thanks!

Most of the pecan trees I see are native pecan trees and a lot of them are about five feet from other trees.

In orchards, they take account of how wide the tree will be at maturity.

My suggestion would be to plant them where you want them.