Caveat: I personally did not train following Hampton, so I am not familiar with the exact details of his method.
First observation: You are obviously already applying a lot of thoughts and critiques to your own drawings. This is great. (I should maybe do that a bit more myself)
Your lines look purposeful and clean, that is always good.
About your construction method,... I don't know how Hampton does it, but I personally found that my construction of the human form made good progress, once I found a good abstraction of the ribcage and pelvis first, and then the placement of the joints as a next step. I see you are using the pelvis, but so far you don't include an indication of the ribcage. Instead you mention the spine.
I guess the logic of focusing on the spine is to make it easier to progress from an initial line of action. I am a big fan of indicating ribcage and pelvis first.
a) Ribcage isn't a very complex geometrical form to incorporate: more or less a flattened upright egg, with the underside cut off along the lower ribs.
b) The ribcage pretty much defines the center third of the spine anyways, so finding the ribcage already answers a lot of questions. Add shoulder joints, head, and tissue (muscles, breasts, body fat, as needed), and you are already done with the construction of the upper body.
Can I ask what specific technique you are using? I would like to know other gesture methods for different uses, kind of like a toolbox.
Michael Hampton's method goes from the head cervical, thoracic, stretch of the ribcage to abdomen to pelvis, lumbar, then pelvis. This makes it pretty difficult for poses where I can't see the curvature of the spine.
I finished Stan Prokopenkos "Figure Drawing Fundamental" course, and and also watched some random youtubers on the topic. I strongly recommend watching at least the free courses on the topic, the paid version is more a "go fund me" with some extra content for gratitude, it doesn't reserve any really essential informations.
If the method you try to follow is supposed to include the ribcage, then I understand even less, why you don't sketch in the ribcage. As I said, it is a rather simple geometric form, and best of all, it is somewhat stiff AND defines pretty much one third of where the spine has to go... right down the curvature in the center back of the ribcage. If you know where the ribcage, the pelvis and the head are, the spine is pretty much already defined. And the exact placement of the ribcage is also pretty easy to spot from the front. If you look at the dip in between the clavicles for the top and draw a short line down to the solar plexus, then you already know its exact orientation.