Discovering how a Phonostage influences an 'end sound' has been easy for me to achieve through experience with a selection of Phonstages in use, and compared side by side in the same system with the same Analogue Source.
The learning acquired was enough to let me understand to really discover a Phonostage able to be though of as extremely attractive and not wanted to be separated from has taken many years and a multitude of demos of Phonostages solely in use, or with the permutations able to be created using supporting auxiliaries.
I owned and lived with Phonostages built for me and bought as retail items for multiple years at a time, until discoveries were made that I was to be wedded until l 'death do us part' .
Think of the experiencing Phonostages as a period of going on dates, until the partner is found that is the one to be wedded to. The good news being no rings and no proposals are needed.
Alternatively, Think of the Journey as being enduring, like a hike up a long hill, where periodically the route levels off and then the next trek is endured until the next levelling off is encountered, with the summit being the ultimate discovery (the ultimate Phonostage for meeting one's own unique preferences for a produced end sound is found). The lower down level Plateaus being the periods there have been discoveries made for a Phonostage (a Phonostage that has made a good impression, is being put into service and lived with; but one not good enough to cease the Journey to make new discoveries).
My advice is enjoy the Journey, the discoveries to be made, and the reward where there is no doubt the Journey to find the device that meets one's own unique preferences is over.
My own journey ended up with a group of friends being discovered, Phonostages I am in awe of, where the options are a custom designed/built for me Valve Input / Output design, a custom design / built Valve / SS Hybrid and a custon design / built for me SS model. Additional is options to use other supporting auxiliaries to create a Signal Path, such as SUT's and Head Amp's.
I tried to be monogamous in my initial wedded period, but the designs of other options and the impact they made left such a good impression on me. I was compelled to become less faithful to one design and permutation for an Analogue Sources set-up. Today I am fully polygamous with my option for an Analogue Source I am wedded to.
Talking about Phonostages does nothing of great value, but introduces another to a Phonostage, which possibly informs on a Phon' that might end up on a shortlist.
My strong suggestion is that any produced shortlist will serve at its best if used to arrange demos prior to any purchase choice being made.