Grafting blossfeldia, and astrophytum questions?

[george76904]

I have done a few successful grafts of areoles of mamm. Dehertinia, and some echinopsis pachnoi onto both pereskiopsis and O. Humifusa seedlings. However I would like to know how to best graft blossfeldia and astrophytum, both seeds were in a mix of the genus so I don't know any specifics, but for the future what stock would work best for them to flower on? I have pereskiopsis and O. Humifusa seedlings. Maybe in the near future I can degraft some e. Pachnoi and use them as grafting stocks. Anyway my question, is what would be the best stock for seedlings, and what would be best for flowering. I can invest in other stocks so I'm not too worried about that. But if anyone has any ideas, or would be willing to send me some of what they though would work best, I would pay cash or trade seed for them.
Thanks,
Will