Not silly questions at all, Student.
First, the idea of a "strap" is the width of material in contact with the tree. It is generally thought that the wider the strap the greater the distribution of load on bark and underlying cambium layer. One inch in width is standard.
Second, from the strap to the hammock one has various options that fall into two categories: conventional hanging and the single line suspension (SLS) to which you refer above. The SLS does allow you to use one line for both hammock and tarp.
In conventional hanging the idea is to get as close to a 30 degree angle as possible. If that is achieved then some like a continuation of straps down to the hammock (called a webbing and buckle system) and others like whoopie slings.
In SLS systems the hang angle is not so critical. But that means the minimum material you'd want to use for a suspension is 1/8" Amsteel.
There are several other systems out there. I've seen a video of an entire system made from 550 cord. SgtRock uses much lighter materials with good results. Ther are many opinions and I've not heard of anyone dying or injured ... but you might want to spend a lot of time on this site looking things up -- lots of great wisdom and experience here. I've just scratched the surface.
But Jesus often withdrew to lonely places and prayed. (Luke 5:16 NIV)
He said to them, “But now let the one who has a moneybag take it, and likewise a knapsack. And let the one who has no sword sell his cloak and buy one." (Luke 22:36 ESV)
While people are saying, “There is peace and security,” then sudden destruction will come upon them as labor pains come upon a pregnant woman, and they will not escape. (1 Thessalonians 5:3 ESV)