Hi snooker, and welcome to avast,
You've got three questions, and I can only answer one of them definitely, your second one. If you merge the icons then click on the new single one (which is is essential the main one, the "a" ball), you'll see there's now a menu-entry for VRDB. Clicking that will give you a sub-menu in which one of the choices is to split the icons again. So basically you can change back and forth between one icon and two whenever you like.
I'm not clear about when the first VRDB is normally generated -- possibly it's 3 weeks after installation, which as you may already know is the "normal" or default period between VRDB updates. But you can always "Generate now" if you want to have one to start with. One of the experts will hopefully be along to clarify when the VRDB is first done if you don't "force" generation of one.
As for the mode for updating them, that's a matter of personal preference. I don't use screen savers myself, so have mine set for when-idle -- and for this purpose, "idle" simply means no mouse or keyboard activity. And it's quite happy to grab a few seconds here and there while updating, so it's almost a background process in that mode. Try it both ways, if you like, and see which way suits you better.
Best,
Mike
