Originally Posted by Bubba
Any of the standard 6 foot whoopie slings sold by the vendors here will be fine. For tree straps, 6 feet should work fine as well. You can connect the two via many different ways. You can use a toggle, a Dutch buckle, or a Bloomgorge Elephant Trunk to attach the slings to the webbing.
+1 on any of the vendors. Or, buy 25 feet of amsteel and try making yourself a set...
I personally prefer the inverted whoopie slings with Dutch Whoopie Hook setup, as outlined here:
You can purchase whoopie hooks, whoopie slings and/or amsteel at DutchWareGear.com.