Of course (at least eventually) you would want a sweet cherry to go onto the 'Adara'?

I have that in limited amounts. However I've grown it for years. To make a long story short I tried two sweet cherry and another branch from a cherry rootstock Gisela® 5. [That's two a long time ago -still alive] and [one grafted about a year ago -dead as of 2 months ago]. 

So with 2 of 3 still working it seems there are probably at least half that don't work very well. The one I trust is 'Blackgold', a good self pollinated sweet cherry. I don't trust the listed 'approved' sweet cherries because there is no indication how long they have been tested. 

Eventually I want to make contributions towards the team that established the large collection of fruit trees in the making available of scions from my Adara to have the Blackgold already established to it. So hopefully your idea might be matching mine, but that may have to wait another year for the Blackgold graft since I'm short right now. 

I see it as a healthy situation having a cherry or Blackgold upon a plum root. It was a big improvement because my original Blackgold that I started with upon a Gisela® 5 dwarfing rootstock got very sick and almost died one year. My next task is to index this combination because I don't want to be giving away things (virus') inside it people don't want. 

Please: -is there anybody out there with cucumber seed sources of the strains that index for pollen born viruses that are common to cherry?

PS. Since I trust Gisela® 5, I would trust budding my other clone Gisela® 6 scions to these better but only as a double x double graft to "any other" sweet cherry, but what's the point of it when Blackgold is a good cherry!

Email Marta and ask if she has some Adara.

Good job John! I mistook you for another member Mark. I fixed my recommended scion source now so you would see it in your inbox. Sorry.

Crankyankee, thanks for your scions last year.  They worked!