You could try a top of the line (or one of them) Audio Note Type E speakers. They have full range sound, sound great, and are 95db efficient at 8ohms. The resistance operates between 6 and 8 ohms so it is an exceptionally easy speaker to drive and it adore quality tube gear. With 8 very good watts from a quality 300b amplifier you just might be surprised at the difference in sound from monster amps and Thiel speakers.
That is what I used before I went the SET/Audio Note speaker route.
That is what I used before I went the SET/Audio Note speaker route.