GF,

Equal tension isn't really that hard. When setting the lines, move the
boat to release the tension. All lines should go slack together. When
restoring tension all slack should be taken up together. Now, this
doesn't mean they are set properly. Wind and tide will vary the
direction of the load and adjustments may have to be made to compensate.
That is why lines are use, because of their ability to stretch and
equilize the load

Ole Thom