With this density (mostly) paper white and a little black, I over expose 2 stops and then adjust level so that the whitest value is about 245 or so (out of 255) them pull the black values down but keep as much shadow detail as you can. Also (for B&W)before adjusting the level I usually reduce saturation (typically -90) this would be different depending on the color cast you want based on the original.
regards
Richard