I don't know about cherimoya variety name, but I always grow them from selected seeds from fruit that I like. In the right climate, a fast grow plant can have flowers in 3 years from seed.
In my experience, the fruit shape as a pipe cone has more complex flavor, more acidity, to my liking. Those with oblong iregular shape tend to have a very sweet as sugar -- just too blan sweet for me. The trick is to know when to pick the fruit from the tree: if it's about to fall off the tree then it's too late (loosing the taste/flavor), and eat it before the white flesh turned to darker color (over ripe).

Don't waste time with a graft tree. Best from seedling.

Sapote