Thank you for the comments. I used 2h pencils a long time ago, to avoid mistakes too, but it became bored for me, i still use that, but only to guide my self on traces, simetry edges, etc. So, if i have mistakes using "b" pencils, i draw over them or i emphasize them, if i destroy the draw, well, i make a new one. I don't clean the lines, definitely. Sometimes i start making stains even using charcoal.
I liked a lot your draw because they had a clear intention for me. Keep it, and take the risk to start with dark pencils