Prussik allows the biner to slide when line is slack, so you can adjust it's position... but it's tight when the suspension has weight on it. That's a good rig!
My preference has always been to use slip knots, and avoid hardware. I have never needed more than 4' of line on each end, but I spend a lot of time in the rhodo jungles of North Carolina.
There are so many ways to do it, I figure that's best left to the Gear Boxer...
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