Thanks for the post Colin - I read the thread you referenced.
Being that I'm a climber first, I'm well aware of how force is multiplied when the angle between "anchor points" increases (see the middle column of the chart on this Wikipedia page for a simple explanation: http://en.wikipedia.org/wiki/American_death_triangle). For this reason, while I think Warbonnet's method (and my theory posted above) for attaching tie-outs, although creative, is ultimately a bad idea: Let's say the corner of your tarp has 100 lbs of force on it. At 90 degrees, Warbonnet's method will cause each leg of the tie-out to experience 71 lbs of force, for a total of 142 lbs - quite the increase.
For this reason I created a new tie-out design where I staggered the attachment points by 45 or so degrees. This results in only a slight increase in force (using the above numbers the load of 100 lbs is increased to 108 lbs), but I'm able to spread that force over way more area on the corner of the tarp than previously (the traditional tie-out design that you see in 99% of tarps out there).
It's a little more time-consuming to build, but from now on I anticipate all Virga tarps to have the staggered tie-out design. I will be putting it to the test in a few days when I take my latest Spectre tarp to the Sierras for two weeks.
Additionally, I'll post up some photos of the new design (it should all make sense once you see it) on Virga's facebook page ASAP.