Best speaker for medium to low power tube amps??

I need advice on speaker selection..they will go in a 19' x 13' x 8' room..my budget is roughly 5k, open to new or used..tube amps roughly 20-70 watts must be the ideal match for these..narrowed my choices to the Merlin VSM-M, Sonus Faber Guerneri, Quad 989 and am open to other suggestions..I'm currently leaning to the Merlin but my only reservation is they are so revealing I will be changing components upstream continually and never finding sonic happiness..thnaks in advance for your responses.