Congratulations on your new Omegas, Dave. I think you'll find them an eye (ear?) opening experience. I have a room very similar to you, and was running the Harbeth SHL5+ in it, when I happened upon a pair of Super Alnico Monitor XRS - let's put it this way, the Harbeths are world-class speakers but they got sold and I never looked back. Once you experience the speed and clarity of an Omega single driver design, it's very difficult to go back. Everything else tends to sound syrupy and slow.
Now, what I will warn you against, is the flip side of that equation - when you're going from a speaker that has a much larger, fuller presentation, to something like Omegas, at first your brain might think you're "missing" something - that it sounds lean. Give yourself time to adjust to it, of course. I was taken from the first second I heard them because of the pinpoint detail, but at first I also was conscious of feeling like I was missing some weight and heft to the sound. That quickly faded and I was left in audio nirvana.
In my room, what I've figured out is that keeping the Omegas relatively close to the front wall - 2-3 feet or so - helps with bass reinforcement. I am probably trading off some imaging/soundstage but for me it's worth it. And it's not like in a room this size I have all that much choice!
I've also discovered through much experimentation that height plays a big role in how I perceive these Omegas. Even adjusting their height by an inch or so made a huge difference in bass and the imaging. This may not be true for everyone, but for me, in my listening position, in my room, it's been crucial. I'm not sure if with the Super 8 XRS you have the ability to change the angle/tilt, but it might be worth keeping in mind as a possible tweak as you're setting things up.
And finally, I went a long time without a sub, but recently added an REL T/5i just for fun. It's neat, especially on recordings where there is meaningful sub bass energy, but I could totally live without it - and did, for a long time!
Good luck with it! Keep us updated!