I did a few side grafts 2 years ago. I didn’t know much then, so I did not top the tree above the graft. I inserted them on branches, not the trunk, and put 2 of them at good angles, I wish I had done them all at this angle.
Not cutting off the branch above the graft did seem to slow down the growth rate, but the resulting graft is solid. May be the slower growth allowed the graft to heal well. At any rate, this year( 2 years later) 3 of the 4 are producing apples and they seem to be holding up very well. That said, they do not have a heavy load, only 2 apples each. What will happen in later years, 
who knows???