That's what I used and it worked well. My first attempts with the pencil trick failed, then I actually tested the continuity (resistance) of a 1/4" dark, repeated line of pencil lead on paper compared to the same distance with auto defroster grid paint (available at parts stores or a GM dealer in my case for about $15). Pencil lead has very poor continuity and I'm surprized it'd work well for anyone. Another idea is to get some cheap $3 magnifying glasses (Walgreens for reading), I used a 3Xs so you actually see what you're doing, then scratch off any extra paint that might flow between the bridges.