Users in that discussion suggested options beyond plain paper, such as dot grid for better structure . To make sure I'm giving you the best recommendation, A notebook/journal (like Sterling Ink) or loose-leaf paper ? Specific features like dotted, lined, or blank?
For high-quality paper suitable for fountain pens, researchers and enthusiasts often recommend: ramming rebecca
A source mentioned in the thread for A4 options with high page counts (240+ pages) . Users in that discussion suggested options beyond plain