Really nice work. Kudos for actual foothills, and for forests that extend into the mountains. Are all the gray zones eventually to be mountains?
I'd call your experiments successful. If you want a subtle shading effect, intentionally eschew precision: look at my Jantoos Bogway map for "good enough for background texture" mountain shading. Probably would suffice for foreground mountains, if the linework on the mountains is nice (yours) as opposed to exceedingly mediocre (mine).
Already looking like a great map - I look forward to seeing it progress!