bearisgray

For the first borders I also measure in three places - I lay the top out flat and then measure both sides about six inches from the edge and down the center and take an average of the three measurements.

Then I cut a strip several inches longer than that (I'm a cautious type) on the lengthwise grain of fabric (If I have enough and/or the design "works")

I divide the border strip as illustrated. I also divide the quilt edge the same way.
Then I match up the points.

Then if one side needs a little bit of easing, it's distributed fairly evenly.