@george53 You have a pretty big room so I would suggest no smaller then a 12" and probably two. You haven't mention how you have the room layout and any room treatment. Integration is the key if you know how to mange it.
Add a subwoofer?
I run a pair of Cornwall 1’s driven by primaluna, VPI, and Sutherland 20/20. Room is 34 x14 x 14 high. I love the Klipsch, but never felt like they were overly heavy bass. I’m curious about a subs ability to “fill in” the sound. I called a dealer regarding REL’s smaller products. I was told that the Cornwall has huge bass and I’d need a very large sub to notice a difference. Really can’t afford a quality big subwoofer. ie thousands of dollars. Not wanting thumping bass, just fuller sound. No experience with subwoofers so, ,,,,
Thanks for your input.