Let's compare the furoshiki sizes using the Hime Musubi Adeline KLAM collection.
Here is the image of a comparison of 50cm(19.69in), 70cm(27.55in) and 100cm(39.37in).

Surprisingly, 50cm(19.69in) size is capable of a simple bag.
Plus, it is able to use with furoshiki patchin mini.
The capacity of the bag is not so big, but still usable like a small pouch.

70cm(27.55in) makes a good combination with furoshiki accessories.
Both Patching and Ring are looking good.

Needless to say, 100cm(39.37in) has a big capacity, and you can use it as a hanging shoulder bag.