I have always done a straight cut for grafting with a corner of a zip lock bag held down tight with a rubber band. Almost every single one has taken but that same method worked horribly for me with plumeria. Here is one I did with a basic single red.
6/15/17
6/4/18
She's grown more since then and has been lifted and cut back.
I will try and get a get a new photo of how the grafts look now while dormant. I think by the end of next year they will hardly be noticeable.