That's what the wife does and then switches to another 0 when that one runs out. I don't like all the screwin' around so just stick to the low one with CPCU as a back up.
Your wife is a smart one, but we already knew that.
Cowgirl? Unless you you have excellent credit I don't know what to tell you.
Chase, Bank America and USAA have been good companies for me (with no annual fees) and I will pay a max of 1.99% interest on a balance.
If you have the credit it's easy to swap balances around. I did it with a home addition (40K) and to pay off an auto loan (30K)
USAA is my favorite and pays me to use them. If you have any military ties you can qualify for their card.
I paid them $0 last year and I received a $300 credit on my card because I use it for EVERYTHING. If I carried a balance on the card it would be 7.9%.
Discover was another card I had. They also gave me a rebate, and I carried balances on the card (at 0%) for at least a year (balance transfers)