Creating better nebari on drake elm using air-layering techniques?

Years back, I air-layered a drake elm and transplanted the cutting to a growing pot. Sadly, I had no confidence in the roots and planted them almost a foot down into the pot. Now I have a tree with bad nebari.

Has anyone had success with cutting flaps into the cambium, dusting with rooting hormone, holding the flaps out with heavy wire, and adding just enough soil to cover the flaps and keep them moist?

I want to create a new ring of roots higher than the current nebari.