[metalfish]

I don't know about winter pruning but I've worked on an apple orchard in summer. The trees weren't allowed to grow higher than an arm stretch & the form was like an umbrella, but this ws commercial growing for good crop yeild.

In June, when the apples are a couple of cm's across you want to thin them- to 7 apples for the lenght of finger tip to elbow, take out the smallest/ damaged or poor growers. This means the tree can concentrate its efforts into less apples so they'll be bigger/ healthier.

Then when the apples are a couple of weeks off ready you can take out any branches/ twiggy growth that's shading the apples- sunshine on their skin ripens them & makes them sweeter- and anything growing vertically (known as water shoots, I don't know why) as these won't produce fruit.

Also if you are storing your fruit don't try storing your 'king fruit' these are the apples with a lump a bit like a nose where the stalk attaches. There's nowt wrong with it but that lumpy bit is easily damaged/ knocked off & it'll rot.

Winter pruning is different, vertical growth can be half/ two thirds cut through & benyt downwards to become a fruit making branch, beyond that I don't know.

To be honest we were paid piece rate to summer prune ( 20p a tree) so you went fast to earn your money and no matter how inexperienced people were the tree was always fine & always made a good crop the next year