Specifically on the “seedling” aspect… What negatives would there be from interstim grafting on one? Perhaps an unknown seed planted and grown for a year. Cut close to it’s current soil line and perhaps 10" of BUD9 grafted on, then the variety you want on top of that. Grow in a pot another year, then transplant making sure to put that bottom graft union a few inches below the new soil line. The BUD9 would hopefully root as well.
Is there risk that the unknown seedling might have dwarfing tendencies itself or perhaps undesirable traits? Any strong reason to use something like M111 for this application instead of seedling?
Thanks.