I agree with finding the optimal position. I agree that any one pair should be removed to get out of the other pair's way.
i dont think that this is your first time dealing with new speakers? yes , you are dealing with 2 different speakers, but it seems you are putting way to much into this.
choose one pair to take the time and setup correctly and it wont be done in 5 minutes and might take you a few days and then when you do find the correct position for them, use blue tape to mark their location. listen to them and take notes of what you like and dont like. after you have had enough listening time with those speakers, move them out of the way and then move on to the next pair and do the same thing again.
if you need to do some last minute comparison tests then you will have your blue tape on the floor to where the speakers go