You should try Tubes integrated amplifier as well. Joseph Audio is not really hard to drive. I had them been driven by Aronov Integrated amplifier ( 60 watts push-pull using 6550 tubes ) with a lot of success.
I have a friend who owns complete Naim gears and still not satisfy. Later, he changes to SET. Right now he owns Wavelength Duetto/ Sine combos with AudioNote Speakers. He tries numerous SET before that include Golden Tube SE40, Audion Sterling.. and all SET. He never goes back to Solid State gear anymore.
One guy use Audion Sterling ( 12 watts SET based on EL34 ) to power his Joseph AUdio rm25. From my understanding Joseph Audio is not hard to drive. I had Joseph Audio rm7si signature before.
Right now I'm using Soliloquy 5.0 with Audion Sterling Integrated ( 12 watts SET ). I've tried numerous solid state gears and go back to Tubes.
Good luck.