Either the Volti, or Klipsch Cornwall 4’s would work very well in a large room, and both would sing with the F8. I have the CW4’s in a room a little larger than yours and love them!
Spendor D7.2 Pairing - First Watt F8
I have a First Watt F8 with a Modwright LS100 as a preamp. Considering the Spendor D7.2's to replace my Zu DW 6 Supremes. The Spendor's are rated at 8 ohms and 90db efficiency - their specs show amps from 25 -200 can handle them. The F8 puts out 25 Wats per channel into a typical 8 ohm load and loves efficient speakers. Anyone here running this combination or have thoughts on the Spendors paired with a Class A like the F8?