mustang, bushes planted four years ago to trim for cuttings

mustang, bushes planted four years ago to trim for cuttings. we've had lots of rain so the cuttings are big this year, 12" to too long I had to keep them 6-9" so they stick reasonably in the medium. 4000ppm iba, a bit of fungicide (secret ingredient in seems) and bottom heat on timed mist, mustang is a cherry plum, a sand cherry hybrid and anything with sandcherry it it's parentage is easy to root under mist. makes me want to create more sandcherry hybrids, propagation like this is easier than grafting.