If I recall, I've seen it suggested that one cut their guylines into 2'-3' lengths, with a bowline at one end to facilitate easing linking of the lines should you need longer lines. Of course, your ridgelines will always need to be 7'-10' in length, but you could cut it to the shorter 7' length knowing you could extend it.
With BPL Nano or Aircore line weighing less than an ounce for 50', there's no real need to scrimp on line. Leaving 10' home probably enough of a weight savings to make it worth it.
Being a member, you can read this article about bad weather tarp pitching.