Paper storage and Organization

So I got this terrific 12 by 12 by 40 slot paper tower on ebay and

 stained it up real nice to match my desk, which is to the right which you cannot see.

 I have started organizing my paper, first the solids in sort of a rainbow order, and then I put some of my stacks in the bottom, but I have all these loose patterned papers that I just have no idea how to sort.  Do I want to do it by brand, since several of the challenges I do want certain brands of things?  Or do I want to also do rainbow and take the stacks out and maybe put them on top of the cabinet?  Hmm, that could work, but I am just not sure, will take more thinking!