Is the bark pack worth the effort, the fact that it needs 5 pieces is my first grumble, four fit in a pot together and on two drying frames, which raises my next point, 24hrs to dry birch bark! Thats how long you might leave it in the real world. I would've thought something like 4 or 6 hours to dry would make it more achievable. After all, there is already quite a lot of waiting involved, wait for the pot to fire, wait for the bark to soak, wait for the milkweed char unless you are using another fibre.
In short make bark dry in 4-6hrs and the bark pack only require 4 bark.