I think these are fine as practice. Might help to note how much time you are using as a baseline. Just from the detail these seem to be 3 mins or less. Above 3 mins people will start adding more details since time will allow for it.
For gesture what I've learned is there is no real hard rule around it. So you are doing it right and well, just keep doing more as your bandwith allows to help keep those dexterity and observation skills refined.
The time limit from has several purposes. One is to force you to focus on the essentials, since given more time people will naturally focus on more "unnecessary" details and when starting off those fundamentals are incredibly important. Good detail can't make bad fundamentals look better, but good fundamentals with little details will still look good.
Another point is that the time limit will naturally allow you to do several trys in one sitting, and when it comes to refining dexterity and observation iteration is really important.
Eventually as you practice more and more, you might start setting additional rules of your own to keep things fun, which I find helps me a lot, but when starting, keeping it simple is for the best.
All this to say you are doing fine! Just keep at it consistently and you are good to go.
