1. Unless close to a stack, probably cards. The further back you are, the more the answer becomes cards. Omnis can sound fantastic, but of course, if it's a noisy crowd, you'll hear a lot more of them with the omnis. And more room echo.
2. I would explore acoustically transparent hats. Depending on your hair length/style, glasses can also do the trick, though of course, you will have puffballs on the side of your head.
There are some well-liked types of hat that people use; it's best not to discuss them in public, but inevitably, tons of people will. I'd be happy to respond to a PM about the topic.