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

It’s a worthwhile discussion because it should address level matching and IF ya cant get the inactive pair out of the room at least short the inputs. 

Good that you have REW as level matching at 1k is a joke…. 

Have fun…but also imagine a floorstander with 11 bands of EQ below 120 hz, so ya can put it where it images best..and then adjust the bass….

Auditioning speakers at home can be the most revealing and relaxing method of comparison and well worth the effort involved. 

I've found using the golden thirds location a solid place to start while using something to catch the first sidewall reflection that can be easily moved. A mobil office chair for the listening position was also helpful for me.

A speaker change is a huge deal, good luck with it.

I set my speakers equal distance from the rear and side walks, then fine tune adjustment with a set-up CD. 

To manage room effects, several methods of speaker placement (such as Cardas) depend almost entirely on the room geometry, without necessarily taking into account a speaker's characteristics.  However,  chances are, a near-flat frequency response isn't your only speaker placement goal. I've used a formula that has been referred to as the "Allison Rule", which also can take into account your speakers' bass response characteristics. 

The rule states that the distances from the woofer (or woofer midpoints) to the floor, woofer to the side wall, and woofer to the front wall should be as different as possible (in order to minimize room effects). To accomplish this, apply the following equation:

Middle distance squared = shortest distance multiplied by longest distance.

The woofer height (H) is fixed (in my case, at about 22 inches). For the distance from the front wall (F) , I choose a distance that that seems to optimize bass response of my speakers, consistent with furniture placement and good imaging/soundstage. So I set F at about 36".  The formula then derives the optimal distance from the side walls (S):  36^2 = 1296;  1296 / 22 = 59".   So my speakers are about 36" in from the front wall and 59" in from the side walls. 

This approach works with your room geometry, but allows you to choose one of the 3 dimensions for good bass response (or for whatever else you're trying to satisfy, such as your spouse's furniture placement preferences).  But the optimal distances for bass response vs. imaging etc. are likely to vary (maybe a lot) from speaker to speaker.  

The OP forgot to mention 1 critical thing in his opening statement that make a big difference and the brought it up later: “But for folks who may have another way of testing both their room and the speaker, e.g., when there is a lack of flexibility in the placement”.

If your speakers have a specific spot that they have to reside in because of lack of space or WAF, then that changes everything and if this is the case for this install, why not bring this up initially? Why would the OP state positioning the speakers optimally if you can’t?