Is it possible to really know what you're doing?

@whart 

Thoughtful comments.

I dare say you know what you're doing.  Awesome Horn speakers and a turntable and everything else speaks highly of the wisdom you possess.

What a lovely space you have.

@devinplombier 

I would say that the first step is for a person to determine what type of speakers they prefer. That is, not brand or model; but rather speaker architecture. 

Is it open baffle? Planar? Stand-mount with subs? Active or passive?

Agree 100% - speakers are the most important component because of their inherent colourations and interference effects of drivers with each other and with the room.  But you missed a very important consideration - are they designed to emulate a point source of sound?

Answering this simple question can eliminate 99% of speakers!  Not to mention, antagonising the 99% of audiophiles who own those speakers. 

There is an interesting viewpoint on MBL's website: Company

On questions like the OP posted, the subject is always in the context on one's system. A generality. The most important contributing factor is the room.

@lanx0003 

I agree that a reference / standard needs to be established.  ... This includes precise imaging—where each sound source is rendered with a clear, stable, and locational presence within the soundstage

Those of us who mainly listen to ’classical’ music do indeed have a reference / standard in live, unamplified performances in concert hall acoustics. 

These concert hall acoustics however do not offer a clear locational presence within a soundstage especially if several performers are playing simultaneously.

Try a large-scale Mahler symphony where at times over 100 musicians are playing simultaneously, often loudly.  Even when Mahler throttles back to say, a mandolin solo, the hall acoustics still dominate directivity!  See the MBL reference in my previous post ...

Is it possible to really know what you're doing?

In relation to the above and as a result of my experiences had when it comes to the following:

Synergy   

the combined power of a group of things when they are working together that is greater than the total power achieved by each working separately:

No I do not know what I am doing !!!

The occurrence manifests with no knowledge of the impact to be encountered prior to making an addition that has the capability to produce an End Sound that has  a discernible difference for the quality of the End Sound and hence, create synergy.

Once having had the experience, I am then well placed to make a suggestion that in a particular system a use of a particular device created a End Sound that was spectacular.

Once having had the experience, I am not well placed to suggest doing identical in another system and listening space will create something that will transfer in quality to another system.