I really like the dragons you drew the best. your proportions seem correct for the majority, i'd say you just need to work on the flow of the figure, they tend to read a little bit stiff.
Like Michael said, you have great and pleasant proportions. I feel they are stiff as well. I recommend drawing longer, bolder lines rather than the sketchy lines you have used so far. After pushing yourself to use longer, bolder lines, you will be able to go back and forth, choosing which kind of line will give you the feel and characterization you are looking for.
Your shapes and proportions are done rather well, but I would like to see a less sketchy style and more of a bold, decisive line. You're half way there!