Couple of notes:
1. My optimism comes from the head of the games division at kickstarter, who looked at our campaign specifically and gave us specific advice, and also has knowledge of our upcoming promos and whatnot. His take was that it's very much in a zone where it can make it. Kicktraq is great when you don't have someone with that sort of data (which I did not until yesterday).
2. Remember also that "typical kickstarter curves" are also typically being based around stuff that's not just games... or even if it is games, not just video games... or even if it is just video games, not our specific subset of the market. I was speaking with the guy who was able to just yank all that data and look at it very finely for us.
3. In our ongoing efforts to be pessimistic with monetary projections (that's typically wise), we have been assuming 15% lossage to various kickstarter fees and backed-out payments. The KS fee itself is 5% IIRC, and then it's 3-5% for the Stripe fees depending on what country the person pledging is from. We're assuming the worst and going with 10%. We're then assuming that 5% of the funds don't clear because of failed backer pledges. That's WAY more than is likely, but it's better to be safe than sorry.