If you've already got learning materials on head structure, I don't know that any likeness sculpting videos will add much more beyond taking specific measurements, dealing with perspective distortion, flipping reference occasionally for a fresh view, using plumb lines... etc.? For instance, there are tons of measurements…
How about signing up for a free 3 day Gnomon trial & accessing the tutorials there by Hosein Diba, Zac Petroc or the one on sculpting head planes by John Brown? There's also New Masters Academy & Stan Winston School that have courses dealing with the head.
Hey @Brian "Panda" Choi If I have to give you practice advice then get a skin scan add bunch of filters in photoshop till you can actually see the pores and their direction and either learn them or use as map [example below About material/tutorials :I know of this one David Frylund Otzen VFX Modelling - Head displacement…