Thanks. looks like great drainage. Are you using gypsum on the trees? What other ferts have you been using on the trees and surrounding area? Any soil tests over the 30 yrs? Must be doing something right as they are healthy.
planting clones? If you would like to know if all your work digging and the cost amending holes was worth it .... take one cutting and plant it in the ground next to some healthy weeds. See if your native mycorrhiza performs as well as what you put in the holes. A layer of gypsum for calcium under compost under minimal 3 inch mulch and let it grow.
if you are into experimenting that is.
If not, its okay with me, your plan sounds good since you have healthy trees you know what is what when it comes to your soil. IME many growers have been surprised at the results of planting straight to the ground.
last thing, if you do the test, you don't have to take your best cut, but to keep it fair, not the worst either
Now's the time for me to chillax sit back and listen to what the others have to say
Good luck in every way growin more TREES where there weren't any before