The sketchpad was 11 1/2 inches by 13 inches. It would fit the most common backpacks (the reason I used that one and not an A3 pad). You can get a ring binder that holds A3 page and plastic sleeves. But this is too large for carrying in a backpack so I wasn't keen on it.
I left the mind maps in the sketch pad which meant that I reviewed by default, every mind map until I found the one I wanted. I could have made it easier by attaching colour coded postit flags for subject and even given them a topid header.
By punching the shorter side you can put it in a standard binder While folding doesn't sound like a neat option it's actually a useful one. You can expand on the mind map, list likely questions, add comments for review on the blank back. Use it as a self test for revision before looking at the mind map. You can also flag it with postit flags with a short heading to locate the mind map you want to review quickly
Actually I remembered the foolscap size because I came across it in an office supply store in Laredo. It's an imperial size rarely used anymore here in Australia. Staples and Office Depot are the suppliers I'm most familar with. There I bought the Sketchbooks and Gel pens. The thinner markers are fine you can use them on the side but consider highlighers as an alternative to a vast marker selection. You can use the 5 colours during a review for grouping information if you decide to stick to one colour pen.
Alex