I tend to always carry a long length of rope for various purposes rather than lots of shorter bits - things like dolly knots and sheepshanks take care of excess rope.
What I tend to do is to tie up one end of the rope to one tree (often a prussik knot or similar, since then it can be slid up and down the tree with relative ease), then tie the other tree's loops/knots in the bight. (usually a bowline in the bight)
The leftover rope I take up the tree a foot or two, and then tie taut across back to the original tree to form a supporting line for my basha. This saves on having 2 separate ropes, and means you can carry one longer piece of rope for other uses.