Nicely done!

For scribing, the trick is to make light passes with the tip trailing behind where you hold the handle. You really have to angle the handle 45 degrees or more and use a light touch.

For masking, everyone has their favorites but I like Tamiya 2mm Masking Tape for curves. I apply this and then use 3M Blue Painter's tape for Delicate Surfaces (not the regular blue crepe tape) to back up the Tamiya and protect the masked area.