Wow! This is a great way to study. Metallic surfaces can be very complicated. Especially when you get into the hyper reflective chrome surfaces. Scott Robertson could be a valuable resource for this type of thing. His book on rendering goes deep into this topic. Check it out if you want to really understand all the technical stuff. I also found his YouTube channel that has some videos you might find interesting for this- https://youtu.be/tIaQAK4UPSM?si=6MGmnyY8qItMa6pG For now, using reference is perfect. If you want to try something a step further, try taking the original reference image away and only use your own study as reference for the next drawing. I think your studies are looking awesome. I especially enjoy how you broke down the monkey head. I might knock down the light values on the ears and mouth a touch. It seems like whatever light source is pointing at the monkey is a sort of spotlight that is lighting up the middle of the monkeys face more than his ears or mouth. Its a cool effect that adds a focal area to the eyes. Hope this is helpful. Keep up your in-depth studies!

Hey there! It's a great idea to practice both digitally and traditionally, I see it helping approach gestures in different methods. I think overall what I would recommend is incorporating more variety in your lines, thinking back to CSI lines. I see a lot of C curves currently, which is great for getting fluidity in the gestures, but finding more areas where an S curve could emphasize a change in direction or a straight I line could highlight a sharp turn or edge in the figure would help balance the fluidity and also help bring out the energy and direction of the drawing overall.

I looks like you have all of the important muscles in your drawings, now it's just a matter of figuring out where they connect and how they change when flexed. It's a truly wonderful challenge to take on :) What helps me is to do tracings before I dive into an anatomical study. I find that I ask more questions when trying to work out what goes where beforehand than when I am in the midst of a drawing. You could print out the images and use tracing paper or do the tracings digitally. It also helps me to label the muscles. That's just what works for me, but it could work for you too! I also try to find references to have available, like Richer's Artistic Anatomy and the free app 3D Anatomy for Artists, which is a great way to learn the origins and insertions. I included my tracing of the images you included. Hope that helps!