I didn't want to clutter up the place any more quoting you, but I wanted to pass along to you that I enjoyed your post here (#162). I found it outright entertaining as well as interesting perspectives.
Somewhat like you, I use an 88 Special for center (due to available space restrictions...see photos), two HTM-12s for L/R mains, and Volt-10s for surrounds...in a pretty large room. That gets to the point I wanted to bring up. I don't often see DIYSG discussions specifically addressing their performance in "large" rooms. Having been through quite a string of models of speakers in my room over the last 20 years, it was not until the evolution reached the DIYSG models that my "nirvana" was found. This was primarily relative to output capability, but also without stress and distortion that so many other speakers had exhibited in here. In purely subjective terms, I call the sound quality that is gained "authority."
I suppose there are compromises in everything, but the cumulative positives add up in a hurry with the DIYSG models. Even size compared to output is impressive. What some here would call true high-end high fidelity speakers would have to be considerably larger to have the same output without pretty significant stress/distortion issues. And the controlled directivity is a huge factor/benefit.
Like you, I have not heard the Titans, but also like you, it strikes me as a very good design. That waveguide combo of the Titans really looks like it would be terrific. I could fit them in as my L/R mains, but I'm stuck with the 88 Special. That said, I'm not so sure that I want to abandon the HTM-12. But it's hardly like you have to mortgage your house to have a little fun like that with DIYSG. I bet I'll eventually give a pair of the Titans a try.
You like to type a lot more than me, but ... I enjoy your posts if I can get through them.