Great question. I have an answer for you. Here’s the rolling pin you’ll need.

Bethany Housewares Lefse Rolling Pin, Square Cut https://www.amazon.com/dp/B000810A6K/ref=cm_sw_r_cp_api_glt_i_PW3QVNADABSP3B8TH83W?_encoding=UTF8&psc=1

Here’s a recipe:

https://tasteinsight.com/how-to-make-wafer-sheets/

If you wanted to save on a rolling pin you could lightly spray a cooling rack and stamp the sheets of dough with it. You’d need to turn the cooling rack upside down to make the stamp. You may have to stamp more than once depending on the size squares of your cooling rack.

If they lose their design in the oven simply stamp again hot from oven using the first stamp as a guide. This would probably work just fine as the wagers themselves will be hidden and what you’re really going for is grooves to hold on filling.