Love the new JJ Tesla's, and Groove Tubes makes the Mullard EL34 reissues, as well as the early rock n' roll/country r&b GE 6V6 that everyone is so in love with. I like the SLI-80 for it's versatility most, so I'd be tempted to get a few different types.
KT66's have less power than the 88 or 90, and 6V6 and EL34's are different again, but all should have enough to power the speakers. The transformer is your real issue, not the power tubes, and the transformer is top notch. Slope and type of power is more important with the input tubes and inverters, it won't affect wattage as much.