Rooting offsets of Mammillaria bertholdii

I have two grafted plants of M. bertholdii which have produced quite a few offsets. I'd like to cut some of these off, and root them down in the Spring. Has anyone had experience of doing this? Is it easy, difficult, fast, slow, impossible??

Hi Chris
I have not tried this species but theresae cuttings root very easily for me. I found good rooting with a watering - drying out completely - watering again cycle. Then, not moving them until the following year by which time they have well established strong roots. Moving earlier did not work so well.