Stew, thanks so much for taking the time to respond. Your reply is very helpful!
I actually returned my letter size Manila folders and exchanged them for straight cut legal size ones instead, which makes for a much better fit in my filing cabinet. I'm in the process of completing my general reference filing system, so that will be great to get done.
I'm still having some trouble dealing with my Active Projects, in terms of feeling comfortable in keeping track of them on a day-to-day basis in my "Next Action" notes. A little tricky to juggle my projects this way, but I think I'll get the hang of it soon enough.
My folders for Active Projects, Project Support, and General Reference I'm keeping in the same filing cabinet.
[P.S. I think I may have inadvertently posted this thread in the wrong forum here. Mods, please feel free to move my topic to the GTD forum instead. Thanks.]