Speaker Positioning

I know from speaker position is critical in achieving the best results from a given system. Is there a dynamic way to measure placement of each speaker to make certain they are the exact same distances from back/side wall, cabinets, seating, etc. beyond a measuring tape and listening to the results? Seems to me if minor differences pay large returns, you could be tinkering with this a long time.  Thanks for the indulgence.  
Also, I might add, it is crucial to keep track of and document your measurements and changes, so when you do find a set up that seems to work best, you can go back to that exact set up if you do more experimenting and moving things around.
Now that I have an optimal set up, if for any reason I have to move my speakers, I'll put tape on the floor to mark where they are. This at least gets re-setting the speakers very close and easy to tweak back into exact position with a tape or laser measurer, without starting from scratch....Jim
Even if we acknowledge the theoretical point that most of the room walls may not be “perfectly” equal, room distances to loudspeakers and symmetry of the speakers in the room down to the millimeter, is an incontrovertible fact in getting the finest stereo image a particular loudspeaker will allow; given their design capabilities. 

Even while acknowledging that most room walls may not be “ perfectly “ even, loudspeaker and its measured room boundaries must be perfectly symmetrical in order to achieve the utmost in stereo image localization- down to the millimeter from back and side wall- as well as toe-in. This is an incontrovertible fact!
Thanks everyone. Again, a lot of great tips and education. I now understand why the speaker closer to the side wall is louder!  Glad it isn’t the equipment.  
Purchased the Bosch laser . Am just waiting for new speaker stands because tweeter position currently too low. Decent subs (vintage Kinergetics stereo 2-10” sealed boxes per side) make the back wall disappearance not much of an issue as those jawns pulse! Planning to get further away from back wall and relooking at R-L distance. 
Will check back at completion anticipated before the bird lands Thursday. 

My new listening room is 100% symmetrical.  I found a space closer together and further from the rear wall with the help of two friends as the Focuses weigh 185 lbs.  I use Hallographs to fine tune the focus of the speakers (funny, Focuses need to be focused using something else).  My new speakers will weigh 600 lbs. each.  I don't know how the installer is going to move them around so that I can fine tune them.  I intend to place them where the Focuses are.  Maggies are relatively lightweight to move to find their optimal position.  The good thing about the new speakers is that they have multiple adjustments for ambiance and bass (with rear tweeter and sub bass units).   600 lb. Evolution Acoustics MM2s and 3s are similarly adjustable.  I guess they suppose that perfect placement is too difficult to find.