Here's a couple more suggestions:When you sharpen or chisel your pencils, SAVE your graphite shavings. I found a tiny strainer that could sift out the fine shavings, made a 'funnel', and saved what I could in a little bottle cap. That will save you a little time scraping.
I don't know what Nolan would say about this, but it was easier choosing pencils to use by using light, medium, and dark pencils and varying the pressure as needed than to choose from 6 pencils, at least in the beginning of learning how to draw, for me at least.