Stephen's got it right.
Flare is important. So it's right for Ralph to recommend testing that includes it.
But it's a better science experiment to eliminate as many variables as possible.
Contacting will eliminate Flare.
Then later you can do a black box test to measure how much flare you have in your camera.
You can paint the inside of a coffee can black and take it out with you and put it in real scenes to perform flare tests, without doing any additional "work". As you take these pictures note the brightness ranges and describe the subjects.