Matching subwoofer

I don't want to hijack OP's thread, but as an Omega user also experimenting with REL I am curious to hear how it goes, as well as what others think.

My Omega XRS floorstanders are rated down to 40 hz, and in my tiny room (11' x 10' or so) I haven't been using a sub.  For fun, I pulled out the REL Tzero that I basically had packed up and was not using, and surprisingly I enjoy it.  However, the Tzero supposedly barely goes any lower than my Omegas, so it's not really extending the bass as much, as boosting it.

I'm now wondering if I should (1) get another Tzero and run a stereo pair, since I like what Tzero is doing; (2) forget the Tzero and get a bigger subwoofer with a 10" or 12" driver, to get some actual bass extension; or (3) do #2 but get a stereo pair of the bigger subwoofer.

On one hand, I don't have much experience with subs, so I don't know what I'm missing by using the one Tzero.  Would performance be much better with another Tzero or a a bigger sub?  On the other hand, I don't want to end up with a sub (or subs) that overwhelm my small room. On the other other hand, I've been told in other venues that a bigger sub doesn't necessarily put out "more" bass, just lower bass - and that I really should go for a bigger driver.

Curious if anyone, including OP based on this recent experience, have any thoughts.  

Zm I was wondering what the t zero would do as well so Thankyou . I just want to reinforce the bass not get down to 20hz. My listening area is 11x13 but it’s an open concept so the room measures much larger. I always wondered I’d Rel and the dealers were steering me to the 7i because of the amount of bass the room needs or what the omegas need. I’d love to try both. My room acoustics have improved but I know that to get it much better I have to add items my wife would be opposed to so it’s a compromise.

Why Rel and the dealers