I must say that my GFR Corner is by far the best sounding. Even then that needs internal damping and specially chosen feet for support to get the best from. So yes I have to agree with others,the larger the cabinet the better the sound. It just becomes far more relaxed and easy going, the sound is allowed to breath and decay more naturally. with a presence and size of sound stage to die for! Not that the smaller cabinets are not fun to listen to. However, the sound varies greatly from cabinet to cabinet and the crossovers are also an important part of the overall clarity of the sound. Also support is important. I would never plonk any tannoy speaker directly onto the floor, you lose a lot of bass and mid range definition, you need a stand to bring the treble coax to ear level and a quality stand from 'something solid' or Target. Furthermore unless the crossover is at its best or the cone at its best, a supertweeter such as the Tandy/Genelec will be needed to add detail and extend the sound stage, opening up the sound- forget all those expensive supertweeters, even tannoys own versions, they just do not integrate well with the old Tannoys- All I can say is that to my ears the 15" versions are the most musically -emotionally- communicative. The original crossovers are probably more musical sounding but less transparent than the ebay newer crossovers you can now buy.. The caps need changing and the treble boost pots need deoxidising - that is just a simple liquid spray job into the pot. Amp wise I have used solid state and valve. The larger the cabinet the better the speakers respond to valves.
I have owned the newer versions of the Tannoy Canterbury and would not go back to them. The 100-200l cabinets need working on e.g the Berkeley port holes need taming to get tight bass and some rockwool at the base, then you will have a less dull sounding speaker with over blown bass. The crossovers also need servicing to get more clarity. Re conning will allow a cleaner and slightly more extended top end to emerge but 4-500 quid is a lot to pay. Once you get to the GFR Corner, the less the crossover and driver condition becomes an issue for high quality sound. I have enjoyed all the Tannoy 15" drivers, from the HPD's to the versions from the 80's but I guess i prefer the HPD or golds for musical enjoyment.
However what you will get from all of those 15" drivers is a realistic full blown picture of a musical event that very very few other speakers manage, with a musically involving joy from them. But you will need to work on them to get them not to sound dull , veiled or transistor radio like, as some have described them. Also careful of high frequency prominence if you have a non original crossover, those original transformers may have more to do with the sound than you may be led to believe when it comes to musicality and tonality but not necessarily detail and transparency. The newly made boards are brilliant for clairty and detail and still quite musical sounding too, but again careful matching needed with speaker enclosure. I personally at this time prefer the originals.