Oops! Sorry. You're right. I got so carried away I forgot to answer your questions!
When I send out to agents or to publishers I try to follow their guidelines as closely as possible unless I have some compelling reason to do otherwise.
Most often this translates into the first three chapters along with a synopsis of the entire novel. My synopsis is three pages long but I've a tighter one-page version for those who insist it be no longer than that.
I send a one-page query letter as a cover to all that with an attached 1-page bio.
The "best" rejection I've received so far was from Meisha Merlin Publishing by whom I would've been very pleased to be published. I've also had a few "nice" ones from Donald Maass although when I saw him in person and thanked him for that he looked at me askance and said he doesn't usually write rejections that go into such detail (of course he didn't know me or anything). I said, "Well, you did me" (I should've taken one of them) to which he replied, "Your story must be pretty good." I let it go at that.
I've sent to both agents (more of these) and to those publishers that accept unagented manuscripts. There aren't that many and I was told by Victoria Strauss (a midlist fantasy novelist whose work is published by one of the major houses) that while they accept unagented submissions, they don't tend to take them as seriously as they do manuscripts submitted by known agents.
In any event, Meisha Merlin and DAW and Baen and TOR all accept unagented scripts (I'm talkin' in the fantasy/sci-fi genre here). DAW recently form-rejected me but invited me to re-submit, which I found odd from other info I've gathered. Right now the novel is with Baen, also an imprint by which I'd be pleased to be published.
A few agents and/or publishers request entire manuscripts, such as Baen. This particular practice makes my husband nervous. He thinks it makes it too easy to have your work pirated if they have your whole book. And he's right.
Usually if an agent or publisher likes what they get they will contact you and ask to see more (if you sent a query alone or if you sent three chapters). They will often ask for an "exclusive" at that point -- for so many weeks or months --so they get "first right of refusal."
Basically what's been said on here before is about the bottom line: send, send send. Re-write, re-write-re-write. If you don't get your work out there, no one's gonna see it. You won't get any feedback. Feedback might make you wince but it'll make you a better writer.
I always think of when I played basketball in high school. My coach would tell us that if we dribble the ball all day, we'll never score. You have to shoot the darned thing -- even if you miss the basket ninety percent of the time -- to even have a CHANCE to score, eh?
Stop dribbling and shoot.
garrie