I really like the concept, but I’d like to recommend an exercise to you. Hide the rider, leaving only the snail, saddle, and any other accouterments on the snail visible. Now fill everything with the Flat Color material set at white, and make your background completely black. Now take a screen shot of a perfect orthographic side view and bring it into Photoshop. Then just make a new layer and start laying down some strokes to make the silhouette less vague and lumpy, and more dynamic with an intersting flow to it. When you have an improved silhouette designed, you can use that as a guide to tweak your ZTool in ZBrush.
Take it or leave it, but that’s my suggestion 
-Dustin