sizing- going up!

Hey fellas, 18m with a Prince Albert here. Currently the only jewelry I have is an 8ga CBR and I want to get a 6ga curved barbell. Here's what I have to consider. If anyone needs reference pics I can post in comments just ask.

- If I'm sizing up in gauge and having a different form factor... I currently have a 1" diameter. should I change that diameter?

- I've had some issues with the ring rubbing the skin on my glans red because I'm not a pre-cummer. Or, that's what I thought.. until I posted on reddit and was advised it's likely a material allergy. Guess I'm sensitive.
- Should I get silver jewelry? Black? Blue? Copper? a like, black stainless would be cool.
- What else should I know?