I use around 12ft total of 10mm static for use with a ropeman 1 instead of a prusik and have a figure 8 on each end.
Here's from a different thread:
kenn1320 said:
↑
Tie a figure 8 or splice an eye loop. Go out to the woods and pick out the largest tree you plan to climb. Wrapped it around and through the loop like normal, then you have the length. Thats how we all do it, no special length works for all.
Click to expand...
Agree with kenn. The size of the tree's you hunt will be the biggest determining factor. Typically after knots my tether ends up being around 6 foot. I've had a couple tree's this year that it was just long enough.