I hope you realise that your tree is a sour cherry ladycosmos, since you mentioned 'eating' them. I have this variety too. In more than ten years I have only really pruned it hard once and then only because the long thin branches were almost touching the ground. I get a huge crop every year - pitted and frozen they last me all year for pies, jam and compote (great with porridge in winter!). I usually trim excessive growth and dead branches when the tree is dormant.
My tree is about 1.5 m high and wide grown against an east facing fence. Biggest harvest was last year, 6.8kg. It was quite a chore pitting them all
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This year the tree has shed quite a lot of imperfectly pollinated fruit, probably due to the adverse weather, but there will still be a very good crop at the end of July.
Tricia