I dunno, i draw since i can hold a pencil kinda xD Its hard to tell how long time pictures take for me since I cant workt constantly on those (only a few hours after work..) But mostly I need around 6 hours for a big picture? Open End of course.. and smaller pics need way less time.
You have to use the medium you like the most and you can handle the best. I cant tell what pencils you have to use since there's no rule for Art what Pencil or what paint is the best. Just try out and see whats the most fun and what satisfies you the most.