Not sure about how you tie off your ridge line for your tarp or rain fly. Separate lines , one continues line tied to each of the two trees or if you set up a continues line which is adjustable like the one in the below link.
I use to do it the hard way by tying off each end to each tree with a Taut-Line-Hitch Knot , then adjusting the rain fly over the hammock by adjusting each knot on the line, Not anymore.
I have switched to one continues ridge line which is adjustable without untying it. Easiest way to explain it is this short YouTube video by Derek Hansen.
https://www.youtube.com/watch?v=C-IkTg4z6UY
All that is required is the line , two carbiner's and a short piece of line used as a Adjustable Prusik Knot.
( I did 4 wraps on mine. )
How to tie a Pruisk Knot.
https://www.youtube.com/watch?v=6mwmlprswFI
I use to do it the hard way by tying off each end to each tree with a Taut-Line-Hitch Knot , then adjusting the rain fly over the hammock by adjusting each knot on the line, Not anymore.
I have switched to one continues ridge line which is adjustable without untying it. Easiest way to explain it is this short YouTube video by Derek Hansen.
https://www.youtube.com/watch?v=C-IkTg4z6UY
All that is required is the line , two carbiner's and a short piece of line used as a Adjustable Prusik Knot.
( I did 4 wraps on mine. )
How to tie a Pruisk Knot.
https://www.youtube.com/watch?v=6mwmlprswFI