POTC Cloth Key Drawing

I've decided to continue to expand my Pirate collection after getting 2 Disney park rings a few months back. I didn't want to be too big of a project, because I've still have to finish my Grail Diary (It's been on hold for a while now). As such, I've decided to recreate the key drawing:


I've looked at few screens and at pieces done by other RPF members, and there is still a few questions I have.

• Are there any exact dimensions? ( I don't have a key replica to base it off of)
• Is a pencil or marker/sharpie the most accurate for the drawing?
• Any tips for getting that unique worn look?

Thanks for the help.