Welcome to the wonderful world of vacuum tube audio. A word of caution on SETs. In your OP, you talked about classical, which can have a very wide dynamic range. Although your speakers are quite high efficiency, these peaks can require lots and lots of power (logarithmic relationship between volume and power). This is important because an SET amp's distortion rises quickly with power output.
A 300b SET makes about 8 watts. Even if you do not drive the amp into clipping, you may start to hear that distortion as a kind of harshness and a loss of the SET "bloom" for which the amps are prized. Depending on your room size, listening levels, etc., this may or may not be a problem for you. In my 14 x 23 x 8' room, I eventually gave up on 8-12w SETS with 94-96 dB speakers, even though I listen to music that does not have the wide dynamic range of classical. I settled on 2 amps having 30 wpc; one OTL and one push-pull. Lastly, do not get hung up on topology or tube type. Once you get past basics, it's implementation (and for non-OTL amps, transformer quality) that is/are key. There are GREAT tube amps using OTL, PP, and SET circuits, with EL-34, 300b, KT-88, EL-84 etc, etc power tubes.
And +1 to the idea of a tube pre-amp.
And +1 to the idea of a tube pre-amp.