No experience grafting Asimina but sounds like you could do it thogh it will be a more delicate procedure.
What tools you use to graft Asimina?
I am friend with the biggest grafter of pawpaws in Europe.
He is from my county but also has a home and nursery in Italy.
All the Sunflowers and Prima that are sold in Europe are grafted by him at his home.
He sells professional grafting scissors of high quality( i think made in Italy) wich he uses also to graft the pawpaws.
Sadly his mother had coronavirus and i dont know anything about him from about a month or so.They were the first persons to bring coronavirus to my county.
This is the plier he uses to graft the pawpaws.If you want this grafting tool,let me know( costs 45 dollars).
https://youtu.be/PTWsogtWCPk