Low volume listening dynamics

A high sensitivity speaker may or may not be more detailed than a low sensitivity speaker. The most detailed speakers are ESLs and they are not so efficient. 
The problem of listening at low levels is that our ears sensitivity to bass and treble is greatly diminished so unless you have some way to compensate for this low level listening is always going to be low fi. 
Compensating for this means loudness compensation for the volume you like listening at. Only a digital room control system with the ability to create custom target curves can do this effectively. 
The other solution is.....just turn it up:)

I am running Klipsch Forte III's (99db) with a First Watt F7 (20wpc) and the combo sounds great at low volumes.

Yes only as good as the first watt! So do you have an idea of the db level your trying to archive at low level? I have a pair of Magnepan 0.7's that have a lot of inner detail/soundstage and are driven by a high watt/current D class amplifier that is very musical to say the least. I normally listen around 72 lb with a few peaks depending on the music With all that wattage and current from my amp the music still has dynamics and energy, even at lower levels 

I listen to music at a relatively low volume, but I still want the clarity to hear the details.

I'll take a different tack from most of the posts here. The most important thing for clarity at low volume is the room. What is the background noise level? Has bass overhang been controlled? First reflections? Slap echo?

The cleaner the acoustic, the more detail you will hear.

Here is a neat article for your enjoyment.  

https://www.decware.com/paper43.htm

It may help you with your quest for low volume listening. It is biased to tube/SET amps, but it also works for any setup (solid state). My latest amp purchase was a 1959 Motorola tube amp that was pulled from an old console stereo. They are real sleepers.

I am using it to run a pair of Decware Imperials. based off of the 1956 Jensen Imperial Reproducer.  Just bought a pair of Altec 811b horns to go with them.

I was using Tube Depot's tubecube 7 to run them. It is a neat little amp and a cheap way to try a set amp at $180. I own two. Got the second one on sale.  It is a toy and the stock tubes suck. Buy some Sovtek EL84s and a 12ax7lps. I have also rolled some Amperex 8bq5 power tubes and a Raytheon 12ax7 backplate in it. All I have to say is WOW!