I feel it pretty safe to say.......
That as long as you don't cut anything above it this year.....the quoted statement will come out to be true.
I haven't wired many elms since they are mostly just growing out....
But on J.Crack, Ficus Benjamin, a couple spruce, Boxwood, and probably a couple others....
I have torn branches off at the top from the trunk, and have split them like that too, and when they heal, they turn out nice....
Thing is, most of the time they end up swelling too far cuz they weren't cut as much...
So yours being cut so far, actually makes it better for a good future look IMO.
My Boxwood, which I split very similar, as far as meat left on, and reverse taper caused...
Has already healed to a point where it grew out the reverse taper and is once again strong with more meat holding it on.
Just keep the exposed wood as smooth as you can, clean, and you should be good to go.
Sorce
Sure, sounds good, thank you . Curious to see the guys grow this season. Got a highly recommended pellet form fertiliser and liquid one too, have a schedule in mind. Should be a good growing season!