I have a similar sized room and similar musical preferences, and also have a 70 watt tube amp, an EAR 890.
I have been through a lot of speakers over the years - Dynaudio C1s, Proac D2s, Tablette signatures and 1.8s, Sonus Fabers Cremonas, Spendor S3/5Rs and 2/3s, and various others. My search stopped with Harbeth - first P3ESR and then M30.1s. Both are good, but the M30.1s are perfect in a small room at low to medium volumes, with a rich, warm and detailed sound, without ever sounding analytical or harsh.
I have been through a lot of speakers over the years - Dynaudio C1s, Proac D2s, Tablette signatures and 1.8s, Sonus Fabers Cremonas, Spendor S3/5Rs and 2/3s, and various others. My search stopped with Harbeth - first P3ESR and then M30.1s. Both are good, but the M30.1s are perfect in a small room at low to medium volumes, with a rich, warm and detailed sound, without ever sounding analytical or harsh.