Needle juniper trunk split

I have a pretty young(around 10-15 years) needle juniper which I’ve struggled to envisage I design for until last autumn when an idea came to me. I have put all the big bends in that I needed to and now I’m going to just leave it to grow. My question is I also need to split the trunk to pull the apex into position, to get the apex to were I want the split is going to be around 6 inches, is this to much to do in one go? And also would this operation to be big to do if I’m planning to repot next spring which I think may be a possibility.