Trellised Annona fruit thinning

[echinopora]

Does anyone have advice on how much fruit load is ideal on trellised Annona?  I thin my trellised stonefruit to one a foot, which seems to give good fruit quality. I have a trellised rollinia with 4 wires, each 10 feet long, 20 inches between wires. I'm up to about 14 fruit set with lots of blooms still coming. Given the size of a rollinia fruit, when should I start thinning?