3 Way Stand Mount Speakers

I’ve never heard the Mac, but it seems to me it was built primarily as a headphone amp and you may be missing out on what your Monitor 30s are capable of. Again, it’s just a comment based on my impression of driving really good speakers from a headphone amp, speaker terminals notwithstanding. But that’s a guess. On a more solid plane, I’ve owned the M30s and the SHL5s and, IMO, the SHL5s presented a larger, more expansive soundstage and are more tolerant of equipment than the M30s, which, again, IMO, are more demanding of better ancillary gear. I think the SHL5s might deliver more of what you are referring to as an "organic" sound, which in my mind translates into wanting more warmth to the sound, especially in the mid and upper midbass. Then again, 50 watts is not that much power for either of those speakers, unless you are listening at very moderate volumes. I would not even think about whether a speaker is 2 or 3 way. IMO, it doesn’t matter. It’s the design. Just one last thought. If you are intent on keeping and using the Mac for speakers and you have a smaller space, consider the P3s. I cannot tell you how impressed I am with them. Given the right setup, they have their own musical quality that I find extremely addictive. And I would think they would be very attractive to an obviously very serious headphone person such as yourself.

Check out the Spendor classic line!
https://www.spendoraudio.com/classic-loudspeakers/

That's a pretty dicey way to assess speakers, by Youtube vids. Like trying to assess how a car drives from a commercial. 

I am appreciating the Wharfedale Opus 2-M2 Speakers that I furtively longed for over the past several years. Finally spied a pair and went after them. Success! Oh, yes, the soft dome 3" midrange IS as lovely as I remembered! No doubt, it's own mix of characteristics, but quite beguiling. I am content at this point, given all the large dynamic speakers I have used, to hold this pair of enormous bookshelf speakers (along with quite capable subs either in the form of the bass module of the Aspen Acoustics Lagrange L1 (preproduction model will give way to production model soon, to be reviewed in owner's review at Dagogo.com), or the Legacy Audio XTREME XD Subs (also reviewed and owned) as my large dynamic speaker system. 

Tannoy gets a lot of eyeballs, but Wharfedale, too, is a venerable speaker maker following tried and true principles and excellent build quality. I have seen very few companies show the extensive pages of measurements in the Owner's Manual of the Opus line speakers. Imo, you need to finalize how much of the boxy coloration you want, much of it with the Harbeth, and not so much of it with others. So, if by "organic" you mean boxy colorations, then perhaps think about whether you want to eliminate much of that. Imo, box resonances are not organic to the music, but actually an artifact added due to design choices. YMMV 

FYI, if you pursue Wharfedale, you will want to look at the speaker posts in the back. On the Opus models the speaker posts are splayed wider than normal, so the leads from speaker cables must spread further. There are some speaker cables that might not do that easily. It wouldn't stop me from ownership, but it could be a frustration if not prepared. 

That reminds me, I need to try the alternative configuration of jumpers, or even doubled up jumpers along with doubled speaker cables sometime! One never knows the superior outcome until the system has been built. Presumption often leads to underperformance. 

The three models to audition are the Harbeth 40.2/3, the Spendor Classic 100, and the Yamaha NS-5000.  Only you can decide which of the three you're going to prefer.

Yea the 40.2/3 are my grails but VERY doubtful I'll ever have an extra $12,500.00+ to drop on them not to mention I couldn't lift them if I could hahahaaa...I'm looking for 85%+ of the Harbeths performance for 1/10th.the $...Yamaha NS-5000?I remember one of my very first systems used a small Yamaha 3 way that cost me like $90.00 & served me well until I moved up to Paradigms something..I'll have a look..
 Re: the MHA-100, I did a TON of research before pulling the trigger..One reviewer used $8000.00 Elacs that are 4ohm nominal dropping to 3.2 ohms with "superb" results..
 Re:U Tube videos are another tool for research & can NOT be discounted as a viable method of demo'ing..