Make sure you keep those cuttings moist in the first few months! We tried exactly the same approach with Sambucus Nigra two years ago and while most of the cuttings leafed out, it turned out we put them in a place that drains quickly so when summer came, there was not enough moisture in the soil and they just dried and died!

And we could not water them, as we're currently propagating stuff in "the wild" meaning in the fields around our new garden, so no easy way to water anything. The good thing is the cuttings came from our own elderberry bush, so they cost nothing and we can just repeat the experiment until successful! :)

ps: Huh, you still have the yurt?