What size (for Coach planners) do you think is the best? I've been debating between the 4x7 and 6x8 for a while now. I just worry that the 6x8 might not work in all of my bags. I only use large bags but I have a hobo that is slouchy so I feel like it might be too big. Plus, I'm worried it might take up too much space. What size does everyone have and how are you finding it so far?