"The key is just to know the limits"
I agree with your comment. I want to have a good idea when something is going to break, tear or come apart. I can then add a margin of error or prepare for the eventuality of the failure in the most weight/cost effective way. Your tarp is perfect for this because we all know it is at the very edge of failure now or in the eventual future. But when will this failure occur and what will be the weakest link that gives first? Inquiring minds want to know. For me it is like watching a serial movie.
The area where I've gone the farthest with this "testing the limits" strategy is my myog backpack. I keep going lighter and lighter on my way to the eventual breaking point. The fabric, for example, has gone from 6 ounce pack cloth to 1.9 ounce nylon to 1.1 ounce nylon with no failures yet. Next version will be out of M50 nylon which weighs about 3/4 ounce per square yard. Regardless of the outcome I've already concluded that most packs are way overbuilt fabric wise. Most of us aren't scrambling over abrasive granite or running through thorn bushes.
Keep up the good work. I've purchased a season ticket for your adventure.