paint pen, metalic ink pens im sure would work....that was just that silver sharpie.
As a student of you alll, I wish that you'd post more "money" shots before you clothe your work. This is the internet after all! The insides are the hard part for newbies like me to learn.
ive got a ton of my solder shots but figure they are boring...you can check the original DIY cable guide and see some of my photos that brschmid put into his guide.