I used some of it to make a really lightweight windbreak. It just gently baffles the wind and like an still bit in a river creates a little pocket of calm.
It also made really lightweight but strong bags to stuff odds and ends into, like short lengths of paracord, and I know someone who made a kind of mini hammock from it to sling under his tarp, but above his own hammock, as a place to keep things at hand but tidied out of the way, from it too.
As a general guideline Jacob,
Grade A is perfect.
Grade B is cosmetically not perfect....slightly faded or discoloured maybe. Sometimes just loom state, i.e. oily/dirty/dusty
Grade C is something wrong with the construction of the fabric. Missing or snapped warps, persistant flaw, etc.,
Grade D is something damaged about the fabric, like a tear or cut.
It's subjective though, Grade B for instance can also mean that the waterproofing isn't complete, but that can also be a Grade C. Every company rates slightly differently.
Only way to be sure is to contact them or get ahold of a sample.
cheers,
Toddy