My first try with this gall a couple of nights ago proved a struggle so I opted to simply spend time on shapes and shadows within the specimen. I think the strategy of study and easy exploration paid off. Last night after some trouble placing in the overall shape I used dividers to measure out key points. After that, things began clicking.
I used the 600 sandpaper for pleasing points, mostly with HB, some 2H. There is very little 2B in this drawing. It took less than two hours for this little piece.