<human>: First time posting on PF and using a throwaway since some of the info is personal. Really appreciate any advice on my situation.

I have two credit cards--a Capital One Visa at ~9% APR and another AMEX at ~12%. My credit line is $30k with Capital One and $21k with AMEX, and I have about $16k in debt on each card. However, I'm a homeowner with a good credit score and I'm not particularly worried about being able to pay these off once I sell my house in the next year or two. Just refi'd as well so not planning on having credit score pulled any time soon.

On to the question: Capital One offered a 0% APR for 12 months on Balance Transfers (with a 3% balance transfer fee). I'm tempted to take advantage of this, but not sure what the smartest thing to do is RE: total credit used on each account and the effect it will have on my credit score (and card rates). Ultimately, I'm trying to reduce the amount of interest I'm paying each month without opening myself up to other issues. Would it be smartest to:

1) continue as-is, two cards with two balances and weight paying down the higher interest rate first
2) move a small portion of my AMEX balance ($4k?) to Capital one, so they're both at a similar debt:credit ratio (~60%)
3) move near the max from my AMEX to Capital One ($10k? more?) and work on paying off the AMEX entirely
4) something else

Thanks for any advice and happy to try to answer questions below.

Summarize the given text in a few sentences.
<bot>: what are some good rules for taking advantage of "0% APR for 12 months on balance transfers" (with 3% fee) that give you maximum savings while not impinging on debt:credit ratio and my credit score?