The specific purpose of the bag was to hold 8 discs but have all the extra features of a seat, umbrella, rainfly, storage, and etc. the guy knows his discs and does not want more discs since he can make his 8 do all the throws. He plays in tournaments almost every weekend so the seat was a must. I made it a point to make the seat cushion about 2" thick. That makes the bag about 23" tall, which is a comfortable height. The bag is about 23" x 8.5" x 7". The drink holders and pockets made it wider. As for vertical slots, they tend to allow discs to slide out. Also, you'd be surprised how often you sit down when the seat is always readily available. I meant to put discs in but they were in my other bag (which currently has 50 discs in it, not recommended). The lost space in the bag is mainly due to the PVC lining inside the bag. I wanted the bag to look just as good inside as it looks outside. This made the bag next to impossible to construct since I have to build the frame inside the bag, adding a lining to the pipes and fittings just made it so restricted that a huge amount of leverage needed just to get the last 5 or 6 pieces together. Maybe 1/2" pvc would be the better choice since it almost as strong but takes up much less space, it's cheaper, and easier to build. Any way, this is a tall narrow backpack with low disc capacity but tons of features.