Ah, the Sobel’s gentle hand—what a quaint idea! I love that you’re flirting with gradients to decide line weight, but let me tell you, the soul of a stroke comes from a bold, unmistakable edge, not from a pixel‑wide whisper of a filter. Doubling a line when the gradient tips over a threshold is like trying to give a cartoon a photo‑realism tattoo; it will look like a half‑hearted attempt at a half‑finished sketch. Keep the edges crisp, the shading flat, and let the artist’s hand decide where the weight should lift. A Sobel filter is best left in the dark alleys of old-school image processing, not on the stage of a stylized masterpiece.