I often find stretch goals in these projects to be kind of dumb. It's not intrinsically true that useful additional material is available to be made. So either it is material that is going to be released anyway but put as "stretch goals" for marketing or its weird stuff of the sort you used to get in "Deluxe editions" of video games, back when those were physical objects. Gewgaws for the Gewgaw Gods.
As far as timelines go, I've backed projects where I got the PDF I wanted the instant the funding period was completed. And I've backed projects where the game didn't exist beyond concepts at the time of the kickstarter.
Is putting 5 or 6 books in one package like this project is doing a smart way to do crowdfunding? It certainly results in a large asking price, which has downsides. But so does putting out all the books in separate projects. But these guys have been in the industry for decades and have experience with multiple crowdfunded projects, so it seems likely they are making informed decisions.
As far as timelines go, I've backed projects where I got the PDF I wanted the instant the funding period was completed. And I've backed projects where the game didn't exist beyond concepts at the time of the kickstarter.
Is putting 5 or 6 books in one package like this project is doing a smart way to do crowdfunding? It certainly results in a large asking price, which has downsides. But so does putting out all the books in separate projects. But these guys have been in the industry for decades and have experience with multiple crowdfunded projects, so it seems likely they are making informed decisions.