How to prune a October Glory Maple to have shorter hight and wider width.
You do not want to prune the leader at all. You will get a bush on a stick. this is a wonderful, glorious tree. Why do you need to keep it short?
The only way this tree should be pruned is by thinning. Thinning versus heading. Heading is what we do to hedges and shrubs. Makes them thicker. Thinning preserves the structure of the tree, the unique branching pattern of a species of tree. Thinning allows for air flow through the tree so that a big wind won't bring it down. Air flow also helps with insects and disease. Thinning displays the beauty of your tree's trunk, branching and definitely aids energy.
When we pruners prune a tree we are doing what the tree would do over time anyway. We get rid of branches that hold photosynthetic factories (leaves and chlorophyll) where those factories will never be able to get enough light to do the tree any good.
We prune branches that somehow got turned around (nursery) and want to grow towards the center of the tree not the outside where the light can be found and always will find other branches to rub against enhancing chances of disease.
Branches from the main trunk that are considerably different in diameter tell us that that branch is not working well for the tree and the tree is already working on getting rid of that branch.
We decide as pruners which of several 'leaders' to chose to be THE leader. Not all trees get extra leaders, we need to chose one. To cut off a leader is like cutting off the head of your tree. That tree will never achieve its natural form. Did you know that some people can ID a tree just by it's winter branching? Its overall form?
Now, there is a way to Pollard a tree. Ugh. Lots of work to do correctly. Akin to pruning a Bonsai. They do this with fruit trees so that they stay short enough for picking the fruit. This type of pruning is up there in skill within the professional pruner world.