Bigger is better for many applications. but there are limits. I EDC a bandanna in my hip pocket, finding it tremendously useful in all the cited applications, even in urban settings. But eventually it becomes too big and bulky to keep conveniently at hand....

If you have a custom maker available, just get an assortment of sizes, using whatever scraps of cotton cloth are available. It isn't like there are ASTM standards.

You can blow your nose with a bandanna, but that tends to decrease its applicability for other usages, like filtering water.

It is common knowledge that red bandannas are more efficacious in all applications, than any other color.