I use my Rachael, 341.5 with K-Horns, Heresy, RP 600, & WF34 Klipsch Speakers and enjoy them. I listen at Very Low to Low Medium volume levels only during the quiet hours where ambient noise levels are at a minimum in a partially treated room, 16*24 w/ 18ft ceilings that is basically open to the rest of the house at approximately 10000 cubic feet of volume.
Sometimes I transfer the amp to my small listening room in a 12*13*8 space. I tend to use the smaller speakers in this room.

For Low and medium low volume levels the Speakers perform w/ vibrancy, have plenty of headroom, and even when not supplemented by subs provide appropriate bass, genre specific. (Club, EDM, techno and similar are NOT appropriate in this setting) Think Jazz, Blues, vocals, instrumentals etc.

I have a lower power SE84USO25 on order w/ even less power available and have no worries that it will perform to my desired preference.

If you can only appreciate your speakers performing at medium high to high volume levels and want gobs of headroom on call for heavy complex tracks I would recommend a higher power class of amplifier.

I too have the Rachel.  Adding a preamp has made a gigantic difference in the soundstage.  Clarity is even better and the detail is unbelievable.  I’m driving Lii Audio Silver 10s.  I stream from the Brinkmann Nyquist to a VTL 6.5 Series II preamp.  Kinda pricey set up but the Rachel is a perfect match.  With tube rolling on the preamp and amp, the possibilities to hear what you want seems endless.

Yes, I've got to say, I am incredibly happy to own my own Rachael - the quality of sound is better than I had ever hoped. Better yet, I have a preamp (CSP2 from Lin) arriving tomorrow, so I'll finally be able to ride the gain and get her set up just so.

On a pair of Randy's Betsy's with Lii 15' I can get her louder than I would ever want before clipping. The imaging is delightful.

The only thing I wish I knew more about was tube rolling; I've been dipping my toes in, and it's a whole new world out there in terms of tailoring the sound for what you like.

Trust me, the wait will be worth it!

When you do get her, I'm really curious how she sounds with those Heresy IV's.

If you search within the Rachel forum (this one this thread is in) you'll see a few previous threads about tube rolling this component that may be helpful.

I've come across at least three members' signatures that list 2x SE34I amps bridged to mono (might be 4-5 members).

Here's a thread from 7-8 years ago in this subforum on the subject:

https://www.decware.com/cgi-bin/yabb22/YaBB.pl?num=1397524062