I know I've heard some people call dry brushing a weak tool compared to edge highlighting, but it can work wonders. I agree with the other poster, and aside from that, I think you are doing a great job so far
I think that drybrushing its an awesome step into understanding highlighting, so definitely think some drybrushing isnt a terrible idea on the carapace. (P.s i am a drybrusher and edge highlighter)