That's a lot of work! As you said, for now it's important to get the vibe and "overall forms", which I think you did. It does seem like as you progressed, lines where getting a bit more impatient and rough.
If at some point you're feeling tired and want to "push through", I'd recommend to take a step back, stop, and move to something else. You can move to the next exercice, then come back to resume later, or work on something else that helps you feel more relaxed.
Many of these, especially env, is a lot about patience, and because envs can take hours, at least personally, it helps me break up the work on them on different smaller sessions so you can focus on one part of the env at a time.
Then again, everyone has different ways to go at it. If you feel comfortable and satisfied with the current way of tackling it, by all means keep at it!