I've been at 5/8" for about 3 years. When I wear my silicone tunnels it works perfectly as a pen holder. I thought about going bigger, but then I realized I would have to buy all new plugs, and that gets expensive.
I used to have my second holes stretched to 00 but it just ended up looking weird. It made my earlobe bulge out oddly.
I think i'm done with mods in my ears, but I do want to get more tattoos. I'm thinking of getting more added onto my left arm really soon. Maybe thursday.