Very wise. My 505 were apparently one month ‘old’ when I bought them and, after now having them three months, they really have matured and settled into a wonderfully balanced musical ‘speaker.
The 606 just ticks all the right boxes for me, looks great, sure - they are expensive - but not as insane priced as some other high end brands, room friendly can be up close to a wall if need be, powerful but refined sound etc , etc.
I can’t speak directly for S10s (though my familiarity with them goes right back to the prototype pair up to the active-capable production model), but I’ve owned C10s since 2008, in the two different iterations: MDF cabinets with jumpers, and HDF cabinets with single wire inputs. I prefer C10s to C20s, for the reason you state. For me the 10 is a more integrated sound across the frequency spectrum. Darned fine speakers.
Both Naim and Chord Ultima amps will bring the best out of Titan 606 speakers. I have heard both combinations and currently own Chord Ultima in the main system but Naim for the other music systems.
I’ve heard the Ultima 5 drive 505, 606 and Titan 808 speakers with effortless ease. The Ultima 6 will drive the 606 well too, as will a Naim New Classic 250 or the NAP300 which was used by Kudos during the development of the 606.
A demonstration at a decent dealer is probably the way to go at this point.
I was told same by the dealer installing my 505. The person who owned them very briefly before me had the dreaded combination of unsuitable amp and unsuitable room apparently.
We really like both but when it comes to price-performance, the Ultima 6 and 5 are very hard to beat. Naim has started to push back though with the new 250.