Welcome Loaniss! As far as I know you can upload as much and as frequent as you want. Personally I can give better feedback to an artist when I see a lot of his drawings instead of a few. I look forward to see the results of your sessions.
These are looking pretty good, especially the hands and feet. On the figures, I noticed they have a tendency to go off the page. I would recommend you start controlling the size of your figure by using simple shapes and lines, gesture drawing. See example: