Looking at specs on that speaker I'd expect 845 to be better match. While I have no experience with Hornings, 90db efficiency and 4ohm nominal impedance, calling for 10-20wpc amp points to 300b SET being iffy proposition. I have both 300B and 845 SET amps, with my Klipschorns, 104db and Merlin VSM-MM 94db, 300B best with Khorns, 845 with Merlin.
I recently purchased Thoress phono, haven't heard yet as streaming has taken precedence. I'd bet on the Thoress 845 being wonderful with the Hornings. Not too many people in US know about Thoress, marketing much more focused on Europe.