I've had ARROs and FORRESTs
One common theme that you will see in many posts and that I also personally experienced: is that they are power hungry.In fact, the FORESTS only performed at their peak when I bi-amped them with hi-current and Hi watts amps
My audiophile buddy test drove the FORRESTS with his CARY pre-amp and tube power amp system ....they sounded flat until he juiced them to a 2 o'clock position on the volume dial... noy exactly a comfortable listening level long-term.
THE POINT: they are not the ideal tube mates in our experience
Take a look at what TOTEM uses to drive them at trade shows: PLINIUS, SIM AUDIO and a select few others. All hi-current hi-watts solid state gear.
SIM are ideal, in fact they are both in Montreal and voiced with each other's kit.