I'm assuming you are talking about this kind of sergeant head or something similar?
For brown, I would probably base with Dryad Bark and highlight with Gorthor Brown, probably shade it with Agrax Earthshade depending on how dark you want it/how stark you want your highlights, and drybrush lightly with Ushabti Bone just on the top edges. For blonde, you would probably be best with Zandri Dust highlighted with Ushabti Bone and maybe drybrushed with Screaming Skull. You could throw a thinned down shade of Seraphim Sepia into that mix, if you want. Just depends on your personal aesthetic preference. Although, you could probably do a variation with Averland Sunset with Seraphim Sepia and then brought up with some Zandri Dust and light Ushabti Bone highlights if you wanted a warmer blonde, almost like strawberry-blonde.