As to the worm sticks: you can also check out how Stackman's party found the sticks in these three chapters (
1,
2,
3).
You can also get a writ by talking to Signeur Pastollio who asks for the writ. If you talk with him and about his thirst. I believe the word "drink" does the trick. He will then offer to give you a spare writ if you give him a cask of boogre brew.