It depends on how 'warmed up' my hands are,& how straight my needle is.... I know,.. I know I should replace that needle, but since it's got that nice bow in it it fits my finger so nice! LOL.
I do maybe 8 or nine, if they get a little bigger I don't worry about it, it's hand work, it's not supposed to look like a machine did it. Relax and do what feels good to you.