Adjusting speaker positioning. What, if anything, to expect?

Mike, Imaging is the ability of a system to recreate the location, size and depth of instruments and voices. It is what stereo is all about. Whether or not a system can do this well depends on the type of speaker and acoustical issues with the room including speaker placement. Dynamic speakers like yours radiate sound over a wide area creating rather loud early reflections off the side and front wall. Early reflected sound arrives at your ears just after the direct sound from the speaker blurring the image like an out of focus picture. This is the problem with the smaller rooms we tend to put our systems in. Late reflections like off the rear wall (other side of the room) are heard more as an echo. They are also much lower in volume. Late reflections do not blur the image and can make your room sound larger if the early reflections are controlled. Bass is another issue altogether. Anyway there are threads that discuss finding and controlling early reflections. Moving the speaker will change the location of these reflections. Moving  speakers like yours farther away from the walls diminishes early reflections and improves the image but decreases bass efficiency. This is a strong rational for using separate subwoofers and the reason many audiophiles keep their speakers so far out into the room. You can sort of have the best of both worlds if you keep the speakers right up against the wall and deaden the surrounding wall with acoustic tiles or panels. Millercarbon is an old school symmetrical guy and for speakers like yours I think he is correct although there are some like Roger Sanders that would argue with this. With speakers that are very directional like horns symmetry is not as important. My system set up is perfectly symmetrical because my brain won't tolerate it any other way. It also can't stand to see a crooked picture. My speakers are ESLs and they are also very directional. 
Anyway, when you move your speakers around pay close attention the image. Instruments and voices should be very distinct and float in space.
Close your eyes. It should sound like the band is right in front of you. 

As I oft counsel the method of moving speakers a little one way or the other and listening each time you move them is far from ideal and can only result in finding local maximum speaker positions, at best. You cannot find the absolute best positions for both speakers that way. The only way to find the absolute best positions for any speakers in any room, regardless of room treatments and regardless of the rest of the system, is to use the speaker set-up track on the XLO Test CD or similar test CD. It’s the out-of-phase track. When you get the most diffuse sound using the out-of-phase track you will get the most focused and correct sound when the system is in phase. Even as your system evolves the speaker set-up track can be used again to establish new best speaker positions. Trying to find the absolute best speaker positions by trial and error is like trying to solve x simultaneous equations in x + n unknowns.

Geoffkait, you automatically adjust phase when you listen for the image. Adjusting phase is only important when you have separate drivers such as subwoofers. Think about that. You can move your head side to side and find the exact spot where two speakers are in phase. It is where the image snaps into focus. This of course is the listening position. Phasing subwoofers is certainly more complicated and the best way to do this is by measuring arrival times which requires a microphone and a computer set up for impulse testing. 

Buy a laser measurement device. I think I paid $ 80.00 for mine and I use this for other projects as well.