Look into a Dennis Had Inspire. Dennis founded Cary Audio, retired and now hand builds small SET/SEP amps and pre-amps out of a small shop in Cary, NC. He sells them through ebay under radioman731. They pop up every now and then, currently he has a NOS 807 SEP amp for $2,800 and a 6V6 preamp for sale.
He built my KT-88 with a volume pot so no preamp required. If your DAC has a preamp volume function you can use that too. The KT-88 drive my Forte III terrific. Superb soundstage and tonality. Plenty of juice to drive Cornwalls to reasonable SPL which have higher sensitivity than the Fortes. I park it in my bedroom rig now where it drives 90 dB Vienna Acoustics Bachs just fine. Sweet little speaker btw.
I concur the R8 @40 wpc too much for Cornwalls, plus it’s a PP, SET sounds much more real with Klipsch Heritage IMO. I park a Willsenton R800i 845 in front of the Klipsch now. At 20 wpc I have inserted an XLR 10 dB attenuator at the balanced input in order to have more volume pot range, but have never gone past 12 o’clock @80 dB peaks.