I like to prune multiple times a year. The benefit is that you will get multiple blooms, and therefore the potential for multiple crops. Each time I prune, I leave several new leaves, but trim all but the petiole. The tree will push new growths from the bud when the petiole drops.
Each bud site has the potential for producing 1-6 flowers, and if the flowers open at different times, then you have multiple pollination opportunities.
If when you bring the plant inside it can still get enough light to produce sugars, you may get a good tasting late crop, if not, you should focus on the early crop.
Doing this you can lengthen your season, though in the case of a containerized tree, you can keep size in check. I suspect a tree in a small bag probably wouldn't be allowed to hold a large crop.
Cherimoya is a plant that responds favorably to intensive management, it likes to throw large vertical "water sprouts" that are best removed to keep the canopy in reach for pollination and harvest. It also likes to push out suckers from every bud site available.
Keep attacking it until it maintains your ideal canopy shape.
I'm finding ideal crotch angles at around 60 degrees for major limbs.