Regarding this comment: "You can simply create a new location in Shopify called "Preorder" or whatever name you want, and stock the preorder product there (and remove from the existing location)." How does that work exactly? I have already installed ...

YES! In addition, their support has gone downhill to the point of being practically non-existent. Very disappointing. Cost is so much higher than it first appears, since EVERY problem has to be addressed with custom coding ($) or an app ($).