Usually it's focal length that is the key consideration for portraiture, at least in terms of making the subject look "good". (I use the term loosely; good is subjective, but let's assume people don't necessarily want to see representations of themselves with huge chins and noses.) You don't mention the focal length of the lens you are using, or the effective focal length you are getting because of any crop factor.
Aperture is a consideration, too, of course, but the main effect is changing the depth-of-field. The "size" of the focal plane (I know, I know, more hand-waving) is more about presentation and aesthetics, though lenses are often sharpest away from either end of their aperture ranges, often 1-2 stops from their maximum.
So, to answer your question, if you are seeing something good at f10, go for it. This aperture is also quite "typical" setting for portraiture (that is, the "typical" aperture is in the f8 range for most longer lenses used in head-and-shoulder portraiture), mostly because it gives you a nice balance of subject focus with less sharp backgrounds. How you use the depth-of-field and sharpness will certainly change how the subjects look.
But, I'd expect smaller apertures to yield sharper images (all other things treated equally), with more pronounced wrinkles, etc., as well as adding more background detail in. The latter may be what you want, or it may be distracting and lessen the impact of the portrait.