Due to an error when purchasing my hammock, I got #3 snakeskins when I really needed #4.
I now have both and am using the #3's for the tarp (in place on the prussics) and the #4's for the hammock and undercover.
The plan is to allow easy setup of the tarp without getting the hammock wet in adverse conditions. The hammock remains nicely contained (and dry) within it's own snakeskins until I'm ready for it...
I haven't taken it outside yet, but it looks as though it will work just fine here in my apartment.