It's hard to believe anyone would still quote the King of Snake Oil (John Atkinson) these days. Even his relative over at AVS has disassociated himself from him.
Everything always seems to magically sound better than products costing 2x, 4x and even 12x as much. Sounds like a huckster to me. If they all sound better than their price, then what prices are being referred to that the sound better than?
Anyway, speaking as the owner of much cheaper T45 towers, the notion one needs a better tweeter on speakers rated +/- 1.5dB over most of their range is absurd. PSB has always stated most of the difference in the price lineups are higher end cabinetry as it's hard to improve on near perfection. I know a Trinnov Altitude-32 owner that mixed T3s with "lowly" CS1000s for overheads and are thrilled with them in their 13.4.6 system.
As for a matched center, the best solution is another T800. If you can afford $12k/pair speakers, you can afford to use an acoustically transparent screen or use a combo dialog lift system (send copies to front heights plus center height) if you're doing a TV instead. I use matched L/C/R and matching drivers everywhere else in a 11.1.6 system (soon to be upgraded to 11.2.10).