Your best bet would be to visit a specialty JM nursery and select a tree that best fits your requirements. Japanese maples can have varying growth habits depending on the graft and how they have been grown so selecting one that has the growth direction and canopy spread you are looking for for that position and siting would be far preferable than pruning one to fit.

Check out Lakes Nursery in Newcastle (should be a short drive from Sacramento). They specialize in Japanese maples and offer a decent selection of JM's suited to a hot, sunny climate like yours. If you take photos of the site it is intended for, I'm sure they will help you pick one that fits.

You should be aware that hot afternoon sun in the summer in Sacramento is not a desirable setting for any type of JM. You may experience a lot of leaf scorch initially under those conditions but even a temporary shade structure while the tree is getting established will help. And plant it in the ground........attempting to manage a JM in a container in your climate is just far more work and trouble than you would imagine!

Thank you for the reply. I was worried about the sun. The tree would be in the southeast corner of the yard and not shaded by anything from the neighbor. It will be cooking for at least three months of the year. It was a VERY hot summer this year.

It does seem like finding a tree that already has the shape I want and then pruning back the quadrants I don't want is the way to go. Tanks for the mention of Lakes Nursery, I wasn't aware of them.

I'll have to really ponder whether or not a JM is the right choice...