Please take at least as much time as you need. Quality trumps speed every time.
The only mystery prize which personally I found not so appealing was the pledge to deliver 1 comic per day for seven days. It sure is exciting, but is it worth it ? I have gotten used to have every single comic come to me as a welcome surprise gift in my In-box. If they come faster then that's great but on a fixed schedule ? Not such a big deal.
At some point during the Kickstarter drive, reading some comments (a small minority of the total, to be fair) gave me a bit of a feeling that we are all a bunch of hungry bloodsucking bats, coming after Rich's lifeblood - ie. his creativity - yelling "more, more !" at the top of our collective lungs.