@mmcgill829 We have a number of customers using Tannoy loudspeakers. From what they report, its apparent that you benefit from more power on that speaker- 60 Watts being a good minimum, unless you have a smaller room! One of our Tannoy customers has run both our tube amps and our class D amp on his Westminsters and reported good results with both, so apparently the speaker is friendly to both tubes and solid state as long as the solid state amp does not exhibit harshness.
Due to the efficiency of your speakers, unless you have a smaller room I would avoid SETs in particular. If you do get talked into one, here's something that you should know: To really hear the SET at its best, the speaker should have enough efficiency to avoid using more than about 20% of full power of the amp. Above that power level the higher ordered harmonics show up on transients, causing the amp to sound 'dynamic'. But its really distortion masquerading as such due to how the higher orders interact with the human ear. Dynamics should only come from the signal and not the amp! Larger SETs also make less bandwidth entirely on account of the output transformer; its very difficult to make an output transformer for an SET that has 'hifi' bandwidth and handles more than about 7 Watts!