the osakazuki tree planted 40 years ago is now 30 foot high. Can it be pruned or a bit chopped off?
Japanese acers can be lightly pruned, most people do 'crown raising' this is where the lower branches are removed to raise the bottom of the leaves away from the ground to make them look more like a tree and less like a large shrub.
you can also thin the branches, but be aware that its easy to cut stuff off, difficult to stick it back on and Acers grow slowly, so it would take years to cover up a pruning cock up.
if in doubt ask a proper tree surgeon, they should be able to help