Careful with masking tape - Sharpie ink smears/disappears with handling off of masking tape. I had used it to mark about 150 wires on a power supply (weird one with 4 big Airborne 50 pin connectors) - the wise old tech showed me some labels he had with 1-100 on them that were on something like the old cloth adhesive tape (think medical) - those didn't smear, but I spent a LOT of time figuring out what went where (you can't 'buzz out' a circuit when the outputs are transistors that you can reverse-bias with the DMM)
