You don't have a "problem". You've got a fantastic new room you're still working on. Spending the time to get it right is half the fun, so enjoy the ride. And yes, you can make those stats you love work great in there.
Our HT rooms are similar -- we've got 4 recliners in the front row, and 3 in the back row, with ML stats (Theos) as fronts, and an ML Stage-X center. The center seat in the rear row is tuned as the primary LP. That's because, with our equipment and room geometry, that gave all seven seats the best possible sonic experience. YMMV
Forget everything about how you set up for your old music room, and start from scratch. Positioning the speakers in space and adjusting angle of orientation (from right to left, and up and down) is especially important for stats, as you already know. But you'll have to do it over and over again, over an extended period of time, to get it just right. Run your room correction software periodically too, and see what that does. Your room, carpet, furniture and treatments effect everything, obviously.
You can use the flashlight trick to help with the R-L adjustments, but mostly you'll have to spend time in each LP (not just the primary) and listen to content you're familiar with over and over again. Focus on content that's rich in the most directional of all sounds, high frequencies, to help you fine tune.
Our riser was small, just under 5 inches, so picking the right chairs to avoid rear row sonic obstructions was key. We recline the front row chairs a bit too, even when nobody's seated there, to give the 3 front speakers a clear shot at the rear row ears. Given our room and furniture, we adjusted the rear feet on the FR and FL stats higher, changing their vertical orientation. Just a bunch of little stuff. Play around. You'll hear it each time you make an improvement.
You got some good advice from Craig and sdolen, because a well-matched center speaker will be huge for you. They offer some good options. After listening to various options and obsessing for a while, I finally bought an ML Stage-X. Worked out great for our room. You still get that great, ethereal capacity the stats offer, no surprise there, but what knocked my socks off was the richness of the mid frequencies.
We'd played The Big Lebowski about a zillion times before getting the Stage-X. After we had it all calibrated, we watched it again. The opening moments, when you first here Sam Elliott's voice, never sounded like that before. Not even close.
Spend whatever you can on your center. It's the most used channel in HT, and will help provide the full soundstage you want
You'll hear different opinions, but I think you can save a few bucks on the surrounds, and plow that money into places you'll hear it more -- your center and/or your subs. Just my 2 cents. Have fun!
PS: Ditto on getting a quote from AVS. Craig took really good care of us. Probably couldn't have afforded the Stage if it wasn't for him.