While watching the first few videos I've started to wonder: If I'd like to add some arms to this bust, would I pull them out from the bust or model them as seperate object and try to attach them to the bust?
This is a great question ttobles. I imagine several people will want to expand their portrait in to a full character (or add to an existing character).
I recommend thinking ahead for what the final state of this character will be; namely clothing. The only reason I would keep the head attached to a torso and arms is if they're shirtless. If they're not going to be shirtless, I would separate the body into as many pieces as possible. Only model skin where it will be seen (not covered by clothing). The reason being that separate meshes can support way more polygons independently than attached.
Through the course my head is workable around 14 million quads but it would be a struggle to go much higher than that. Imagine how many polys for a whole body at this detail level 😖 So the more you separate the more detail is possible as a whole. Just remember that you probably never want to turn all pieces to their highest subdiv level except at render time. Note that I took this approach in the Modeling Realistic Characters Course from several years back.
If you're wondering "well what about a fully naked human body?" I've never needed to sculpt a naked, fully-pore-detailed sculpture before. But we would certainly have to make significant compromises in the detail department. I really don't think Blender could handle a 30M+ polygon situation (at least not currently). So I'd have to figure out pore detail apart from sculpting it...the better question to ask is "why do I even need such a highly detailed naked human?" If it's for a shortfilm or animation of some kind then I would have multiple versions according to the camera angle: Mid-res sculpture for full-body shots and high-res *pieces of the body* for close ups. There would be virtually no way to perceive the entire body and it's pores simultaneously. I should stop - I'm starting to ramble :)
