Hi Lord! I'm right there with you and still working through the anatomy myself. It's exciting when it comes together, but it sure is tough! The advice I'll offer is color coding muscles. Like, once you have the sketch down, color the traps different from the infraspinatus for example. That's helped me continue to differentiate and also more easily track where the individual muscles are going in complex poses. Your sketches look awesome! I like how tidy the shapes of the different muscles and bones are - I can really see where one stops and another starts, which is tricky.