I'm not sure I know what ya mean about the morph target. Do you mean save the morph target of the model before sculpting the details and sculpt on the copy and then use the morph brush to blend the details to the original?
yeah you can set morph target at any point. Do that before you add noise and alphas for sure so that you can go back over the sculpt with the morph brush and it will help you blend in the alphas without destroying the underlying sculpt.
I basically use the clay brushes to slop in form. You can change the alpha to a round one for when you refine the muscles. Be careful when smoothing because you may get rid of some happy mistakes that way. Also make sure when you are blocking in form to stay at a low sub-d. As far as wrinkles you can use the dam standard…