Thanks. Being these trees are too young for acorn production, "shaping" is more the goal....taking a few lower limbs each winter to stimulate upward growth of the main trunk.Always heard and practiced taking no more than 30% off in any one pruning. If the tree is severely pruned the resultant growth has more of a flush and works on vegetative recovery rather than fruit production. (Also keep in mind that pruning and shaping are not the same. Shaping is for structural training of the tree, pruning then works to increase fruit production via sunlight, increase in fruiting buds, air circulation {especially important with soft mast like apples, pears, etc}