Game changer" feels like a strong word for just picking a different background color. It's a gray square, not a magic trick. I get that it helps see values better, but calling it a pastel sketch on white seems like you're making a bigger deal out of it than it is. It's just a setup choice, not the secret key to good art.

Oh yeah, a good flashlight is key. I had to trace a wire in my attic last month and angled the light from the side, almost flat against the insulation. It made the printing cast a tiny shadow so I could read it. A headlamp works even better because it leaves both hands free.