I recently designed and made a reporter notepad in 90x130mm with 50 pages Clairefontaine paper (90g) with my K40 laser cutter to quickly memorize notes, ideas and sketches on the move.

A spiral binding allows the pages to be folded over completely and allows for opening and closure as often as required to refill with paper or to mix paper variants.
Polypropylene covers with a thickness of 0.8mm protect the sheets on the front and back.

A textile rubberband will hold the pages together and will even hold a fountain pen/pen.

Looking forward to your thoughts.