I only set 8 max under my Orpingtons mostly because more than 8 chicks is a lot to keep track of for a free ranging hen. I do let mine sit when they want though, so there are always multiple families running around causing chaos.
Once you get to know your hen’s specialty as a mother you can determine what’s best for her. My early weaning moms (4 weeks or less) get more chicks so they can lookout for each other when she goes back to laying. My long term moms (6 weeks or more) get only a few chicks since they are so mature when she weans them they fit right into the flock. If you have a mixed flock a long term mom is the best choice for flighty nervous chicks like Leghorns. She will teach them not to roost in the trees