I agree - no problem pruning the low branches.
I noticed you have a LOT of areas where multiple branches are originating from the same pair of nodes or nodes very close to each other along the same branch. That will cause a lot of thick knobs, and as those branches die back, entry points for insects and diseases.
I try to eliminate as many points of trifurcation as possible, and all points where more than 3 branches converge (the branch lead + a pair of laterals).
Too, you'll notice your trees habit in spring is for buds to break with each lateral bud pushing a short internode between the next pair of lateral buds. The second internode can be very long, like 12-24" long between the pair of leaves. If you pinch out the branch lead
it will stop the branch from extending and activate buds in the axils of the pair of leaves. So instead of a very long internode with a single pair of leaves 1-2 ft distant from the last, you'll get 2 new branches with leaves close to the previous pair of leaves, so a much fuller and compact tree. Then, next spring, you can prune off the long growth back to the short internodes and do it again. You'll get an amazingly compact/full tree.
I drew this to help people who want to make their jades and mini-jades look like trees, but the 'natural habit' is the same way maple grows. Note, by limiting your branching to bifurcations (Ys) when the tree is young instead of the natural habit of trifurcation (pitchfork - 3 [or more] branches)), the difference it makes.
Al
