@Rek where do you get felt? This is still out of stock https://www.carbuildersolutions.com/uk/inner-window-trim-draught-seal-1-metreThese things are very light - I can buy in bulk and send in bulk in a reinforced tube. If members want me to look into it then let me know.
BTW - the W&N rubber parts needed quite a bit if fettling to get them to fit without crimping. Anyone else had issues with this?