So I have a nectarine and a peach tree that I have had in the garden for only a couple of years now but they are 3+ meters tall and the trunk is probably 50mm in diameter already, I had planned on building some trellis for them and espalier them (basically some nice quality timber posts with some stainless wire.) But unfortunately I didn't do the early work and the idea came later.
I really would like to know if I can prune them back quite hard and would the trees recover without any problems? I know they can shoot quite vigorously, and I know they are grafted varieties so I dont intend on cutting them down to the ground level. what would be an acceptable amount of pruning be if I essentially want to "start again" and encourage new shoots for training on wire?
I will also have to move the trees over a meter or so because I plan on erecting a shed, and I'm trying to maximise space in the garden bed for a veggie patch.
Here is the concept, on the far left and right are the stone fruit trees, lemon tree left from centre, apple in centre and lime tree right of centre.
I will have no issues with the apple and citrus trees as they have a good selection of branches and i can selectively prune them until they re-establish

Here are some images of the stonefruit for reference, photos are from November last year but they are doing well and have loads more growth than the pictures show, if I plan to do the big cut it will have to be mid to late winter so I'm well prepared for the spring and then I can finish off the landscaping

