Can I get my own posters to use as the target? If yes what size do they need to be?

Yes, they are cool with it. Id say the card board they use is 20 inches by 30 inches. You need to take your poster to their cardboard.

Yes you can bring your own targets. Has to be paper that can be taped to the cardboard backing. No Pinyatas or other objects that leave a mess. Have to use the tannerite outdoors...

Yes,you can