A list of efficient speakers at ~$5K a pair.

Fyne Audio Classic 8 Bookshelf should be on your list to hear.

I am searching for speakers that would make a lesser demand on a power amplifier than that of my Fritz speakers, which I do consider an easy load.

Just out of curiosity, why?  Are you sensing your amp is straining or do you think the speakers aren’t fully opening up?  Your room is small the Fritz speakers aren’t a tough load so I’m wondering.  What amp are you using?

These open ended questions will get you the answers you are receiving. What are you using to drive your speakers? I run 93db MHorn Mummy’s with a 12w Tron 211 amp and 17w Miyajima OTL’s in my room which is about the same size as yours and have plenty of dynamics and headroom. I couldn’t use a 2a3 amp but a 300b at 8w would be plenty on these speakers.  If you like your speakers now look at upgrading your amp.

OP

From what I gather, you seem to avoid speakers with low bass. 

in feb nobody seemed to be able to help re: Bel Canto REF 500s amplifier, what did you end up doing for amp power? 

"I am using a pair of Magnapan LRS+ speakers in a ~15x12x8 sized room and am looking for a SS amplifier to pair with my Aric Audio Super tube preamp. "

now

"I currently own Fritz Carbon 7s SE  MK2." 

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I am thinking more info will give members insight, perhaps post some photos in a Virtual System, it's pretty easy.

My take, you can put larger speakers with low bass in that size room, I would try that before mixing subs later to solve the lack of low bass. I'm not talking huge or extended low bass, not swarm, just decent full range capability with excellent imaging. 

I typically advise high efficiency so that it is easier to use Tube amps now or in the future, and avoiding low impedance as you intend is also wise for that possibility. 

Less Cost, Heat; More Options in lower price category, Easier to Place, perhaps Mono Blocks to disburse the heat and split the weight of big transformers.

you can filter by sensitivity and price in the same time

https://speakerchoices.com/

13 speakers between 4 and 6K over 91db