Trying to get my material list togeather to make a couple of hammocks. I'm new at this so I'll have a few questions. I went to Hot Springs to have a look see. Looked at Ed's hammock and he showed me the calendared material. Some places don't list this feature. Heck one local place in Asheville the old ladies in the store didn't even know what ripstop was. Is it even that necessary to be calendard ?How would one determine this over the phone with people who won't know what it is ? If its listed as downproof would that indicate as being calendard ? What weight ripstop is commonly found in retail stores ? They seem to never be marked so how dose one tell the weight while still in the store?