I have a $2,300 line tester that has no opinions on knots, but the simplest method of comparing two knots requires no such equipment. I think this demands a jerk test.
To test two different knots connecting flies, use two hooks from the same box with a knot tied in either end of a line. Grip each hook with pliers and give a hard jerk, and one knot will break. To be sure, do the test 10 times, and you will know which knot is best.
To test line-to-line connections, make the connections, then wrap the two ends around smooth wooden
dowels and jerk.