Hey c_moon, If you don't want to measure using heads, there is another way, you can use the envelope method. You start by marking the top and bottom of your image, then the sides. This will make sure your drawing is the right height and width. Then draw an envelope, or shape that your figure fits into, breaking it down until you have a silhouette of the figure. Then build your structure inside of that silhouette. I did a step by step to show you what I mean, hope it helps :)

I think for the drawing in the middle, the pose is a bit off-balance as the center of mass isn't above the straightened leg. Also, the head is a bit big. Overall, I think you got the gesture down pretty well but it would be better if you really showed which parts are being stretched and which are compressed by using more decisive curves, for example, the left side of the third drawing could've just been drawn with one c curve. Another example is on the right side of the hips on the first drawing, you drew an awkward bump that goes against the gesture. Also for gesture studies, don't focus on the details and shading and try to do them as quickly as possible. Don't rush learning anatomy yet and make sure you can draw accurate proportions first. I hope this helped!