Given how unsatisfying the cardboard runes are to cast, I have created a 3D printable version that has a lot more heft and is quite nice to cast
It prints quite easily on a standard printer then the supports come off easily
Finally paint them and seal them and you have some good runes to cast
You can find all the files on Thingiverse
https://www.thingiverse.com/thing:2457384
If you don't have a 3D printer, any printing service will be able to print this for you, please note you only have to give them the "Runes with supports.stl" file
If you can come to the excellent IBuyWargames store in Woking, UK then I'll print a set for you - it will only cost you a game