The notion of speakers being too big for the room is just one of those unsubstantiated statements or claims that has no evidence to back it up. It’s a non-issue. Choose the speakers you like and don’t reject something that you would love. Audio Note has been mentioned and I concur and suggest a used pair of Snells. Devore are just lovely and do make smaller units that may fit your budget.
The route I would go is to high-pass the mains relieving your low powered amp of transformer saturating low frequencies. If the speakers you choose have ports plug them rendering them a sealed box in performance rolling off at 12dB/ octave. You mention a sub but it is not clear to me if you own one or intend to. As far as I’m concerned subs are a necessity for any audio system regardless of room or speaker size. Even megabuck speakers need them because of unavoidable room modes. When sealing ports on a speaker you are removing additional bass sources which complicates set up. Now some will argue that you will lose bass and you will and that is the point which is to get quality over quantity. Full spectrum balance is achieved with subs (2 always better than 1) and for subs 2 parameters are paramount: must have variable phase and they must be sealed boxes and will therfore match the XO slope of the mains and provides the most seemless blend. Todays subs come with high damping factors unlike a low powered tube amp so there is no worry there because most but not all speakers are designed around solid state amplification.
If you are wondering why any subs are needed it’s because of room modes, that nasty phenomenon that plays hell with your sound. The only way to avoid this is to listen to your speakers in an anechoic chamber or mounted high in the air in an open field. Fact. When you position the speakers for a nice soundstage and precise imaging the bass will be compromised but the 2 subs will smooth that out. No more nasty peaks or nulls
Regarding high passing the mains this can be simply accomplised by inserting a PLLXO in the amp’s tape loop or soldered into the interconnect cable you just need to know the amps input impedance obtainable from the manufacturer. It consists of 1 capacitor and 1 resistor. Look up passive line level crossover.
Check out the link below and look for my 2 posts which goes into more detail on setting up multi-subs
