Hi Pat,
Note...multiple leaders is common with this species of Acer...and they are also very susceptible to "V" leadering...which in turn leads to "inclusions" of all types from bark to branch. This in turn leads to "core/pith rot" (common and natural in Acer ssp) in the tree that could be avoided and/or "cankers."
In your photo, there is "3 leaders," it may seem logical to remove the two outer ones...Ah, but look closely...the middle and outer right one in the photo are not the "primary leaders," they are secondary leaders and already have the start of "bark inclusion."
It is actually the smaller, far left "leader" that is the "primary trunk leader," that has now been "stunted" by the more aggressive "sucker leaders" that have become larger. These two "suckers" are the ones to remove, and then stay on top of the tree with pruning...This species can be pruned year round with very little ill effects. I would also suggest never cutting the "limb collar" and if possible getting a..."20 mm #5 swoop
spoon gouge" to create a slight concavity after the cut. (Remember...practice 3 cut prunings to avoid bark tearing...) This "scooping" is a common practice in advanced Arbor care, Pensai and Bonsai. Limbs treated the way encapsulate and "heal over" much, much faster. I also still "treat" my cuts with a bit of borate wash then
flax oil...I will often mix black charcoal and flax oil to make the cut more aesthetically pleasing and it too seem to make the wound heal faster...
Regards,
j