I thought of making different types of cowboy hats: A leather one, a grass one (or implement a new material: straw, made by drying grass.), and maybe one made by wool. (Felt, which most cowboy hats are made of, is made of wool.)
So: As an example:
Leather cowboy hat:
1 day
300 grams of leather
scissors, needle

Straw cowboy hat:
1,5 days
300 grams of grass (or straw)
Needle, knife

Felt cowboy hat:
1 day
300 grams of wool
scissors, needle

And:
Bowler hat: (also made of Felt)
1,5 days
300 grams of wool
(Maybe 50 grams of leather or something like that, as reinforcement?)
scissors, needle.
