I followed the recipe in the paper I linked here
“root cuttings (15 cm in length and 15-18 mm in diameter) of two-years-old cherry rootstock Gisela 5 were taken in the last ten days of February for two consecutive years. After surface washing and drying, they were placed vertically (leaving about 10 cm above sand level) in bottom heat bench with a cutting base temperature of 17-20°C. They were irrigated twice per week until budding.”
except I used promix HP and didn’t bud them. the same procedure worked for citation. I didn’t use BAP and I did use bottom heat. I think without budding them the take rate will be lower than the 80-90% in the article because you aren’t providing a bud, but still a chance