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not sure probably 4-5 hours I think.
I hope to get faster with more practice
tracing the line-work makes it so much faster, but there is much skill in drawing without tracing, something else I would like to practice.

Thank you for your appreciating

Working for 4 to 5 hours is really a tough job. Yes, initially it takes time but after some practice, drawing becomes much faster. KEEP IT UP.