Speaker shootout question -- do you position the same or differently, depending?

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. 

Johnny, not sure what you mean by "The room dictates the best position not the given speaker" since it would be room-AND-speaker, right?

Generally, the room will dictate where the speakers will be placed within the room, to deal with peaks, nulls, modes, etc.  Once they're in those positions, then speaker toe and rake angles can be experimented with to dial in each given speaker pairs soundstage, focus, etc.

Ideally the speakers should be compared in their optimal sounding position assuming this is a position you are willing to live with. 
 

In my case, the system/speakers reside within the main living space and therefore have to sound good in the space allocated to them. Fortunately, I can place them at least 3’ out from the front wall and at least 6’ from a side wall. So far, this location has worked pretty well for 2 different floorstanders and 2 different bookshelves. 

Tower vs Bookshelf. The baffle width is the biggest thing, so bass is one issue. Second normally a narrow baffle no matter the design of the wider baffles has the ability to collect less distortion on the baffle face and driver face. Narrow is better and phase plugs help even more on a cone speaker.

Bass reinforcement with a decent stand mount is pretty easy. Beard the stand. Simple heavy cardboard will add a lot of bass. From the bottom of the speaker to the floor, the wider the beard the more bass it collects..

Position the speakers every where, I do.. I like  speakers pretty far apart compared to most and I like the long wall as the back wall, usually. Nothing but speaker typed is written in stone for me.. Small planars and ribbons for the monitors.

Regards

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