Interesting, in the same way that learning how to wash your clothes on a washboard is interesting. But neither is very practical for most people. I think I'd just buy some waterproof tarps at the store and be done with it.
Ye gods! Interesting article but I'm afraid just clicking on the link might have landed me on some FBI/NSA watch list! Just an FYI for anyone reading the link is to a real tinfoil-hat-type stuff.
I'm curious/confused about boiled linseed vs. raw. I've read some suggestions that raw has more penetrating power (and more pungent power too), and it can be used to waterproof boots etc. But perhaps it doesn't cure (stays sticky)?
Hem the tarp/bedsheet with small cordage which can be rewoven into a suitable gill net.....Some of the cordage can be fashioned into a bow drill for fire making. Shelter,food, and fire all in one!