LOL anyway about the root pruning, I have had great luck with Q. suber, Q. virginiana and Q. ilex and now Q. gambelii root pruning just before they break bud. On all of the four above the rootball was reduced by more than half in January and all are growing stronger than ever.
(All the above trees were in nursery containers previously so they don't have real good rootage just a few really thick long ones tangled up)
These little fellas in the op will get it next spring. Summer and Fall they are going to get fed like crazy and allowed to grow unpruned.