So I finally got bored enough to try the bag out with the bottom compartment. The only trick was that I wanted the seperator zipped up (if you zip these up, it pulls the bottom material up tight so you don't get the whole bag sagging down). So that meant two small frames instead of a double-level Frankenstein frame.
The bottom now has room for 4 discs or so, or snacks, or towels (my current use), or even a light hoodie. Hell, you could even carry an extra pair of shoes in case you have a disc go swimming and you want to get it back. Since I have a plastic plate anchoring in the bottom rails, and a Plexiplas plate on top of that, water shouldn't soak through to anything I keep down there.
The top just has a simple frame with a couple armrests to hold the discs in better. If you look, I didn't put a back bar along the bottom. Two reasons. First, I don't like feeling those bars across my back, so I try to avoid them as much as possible. Two, this way, I can twist the armrests inwards some and effectively create a smaller disc space if I don't want to carry the full 16 or so it takes to fill the top. Even at 16 (as you can see) the side discs are still easy to pull out.
So if I'm using all available disc space; I can fit 16 up top, 2 in my top putter quiver, 4 in the bottom, 2 in each side. For a total of 26 discs. I honestly only carry roughly 16, so I have a lot of extra space for other things. Plus this brings the bulk of the disc weight up higher, so it should be easier to lug around for a day of discin'.