graft orientation for success

I have an american persimmon sprout growing in my yard, pretty little tree about 4' tall and it has 4 nearly horizontal well spaced scaffolds.  I was planning on grafting 4 or 5 scions onto this tree next spring but was wondering if scion orientation, horizontal vs vertical, will have any bearing on success.  I could probably bend the scaffolds to more vertically if I start now if it matters.  Would removing the central leader increase chance of success on the scaffolds?  All the persimmon grafts I have done were vertical, either central leader to upright limbs.

in my experience, there’s not a whole lot of difference between horizontal and vertical as long as they’ve got enough light and space to grow. reducing the leader can definitely help encourage the tree to put more energy into your side grafts.