I think that if you do get a beta, get a boarder. My beta didn't know anything about the PPC or what you look for. Still, he was better than nothing.

1): Betas are not necessarily related to permission, though in the case of permission you would want to have your stuff looked over first, posted second.

2): No, you don't have to. It's still one of the better ideas, though. There's a reason editors exist.

3): See number two. Very, very little here is considered mandatory, however, there are some things that are so common sense that you'd have to be crazy not to do them. Having a beta or two look over your stuff is the same way.

1/ You ask for a beta before you make your story publically available. If that story is a Permission piece, you'll need to ask for a beta before you use it to ask for Permission. If the story is a mission that you plan on posting after you get Permission, then you'll probably get some very funny looks asking for a beta before you do have Permission.

2/ & 3/ No, beta-readers are not mandatory, though I know a few people who would love to make them so. ^_~ But they are strongly recommended. (Me personally, I think that if you get your samples beta'd without intending to have betas for your missions/other PPC writings, you're misrepresenting the finished product. But that's pure hS-is-weird.)

hS (is weird)