My only
experience with Siberian Elms has been negative unfortunately. I tried to glean a few papers from google to see if anyone has tried this with any success and don't seem to be finding anyone attempting it?
Another forum had someone try to attach apricot via grafting but it failed.
I think this might be an excellent opportunity for you to try.
My first worry, is my main complaint with the tree, that once you nick it they tend to weep and get bacterial infections that inevitably kill the tree. I had a stand of 8 where 6 of them have suffered this fate. I have three more to knock down when I get a chance. The good news is that the chips are gobbled up aggressively by mycelium.