I think it is wonderful when the two are combined. I'd decide which parts are to handquilted, do the machine quilting so those spots are left open ( put painters tape around them, or use wash away thread to baste muslin over the top of the quilt areas to be hand quilted)....then after the machine quilting is done, turn it over to the hand quilters to do their thing. If you use wash away thread, the muslin could be "released" by wetting the area with water either sprayed or wiped on.