I know your space is tight, but what are the dimensions? Could you turn the couch/speakers 90 degrees to gain a bit of depth? You've had OB with rear damping in the past, could you try it again?
How about a front/sides cabinet with styrofoam backing as an extreme/easier pegboard sort of idea? Easier to cut at the store/lumber yard to fit in the car. You could easily cut small holes into the styrofoam to simulate a flexible aperiodic effect, then enlarge/add more holes to experiment. One sheet should allow for multiple trials.
I know you have more experience than most of us here, but glad you spoke up!
Hi Jeff, good to see you here. I do know a lot about OB, seeing as I've been building them since around 2001. That was always in a spacious living room where almost anything worked. This present room, about 13' wide x 15' long, is cramped. I have already changed a lot of things since your visit. I built H-frame OB's for my sub. I can reach 23 Hz with these now. The main reason I built them is to have a platform to place experimental baffles and enclosures. I retired the Betsy drivers for now and have a pair of EV LT-12 coaxial drivers (EV called them triaxial because of whizzer and horn tweeter). I have always liked the sound of the vintage EV drivers on OB's. These sound liquid smooth on the mellow Jazz I like to listen to. I can close my eyes and almost smell the smoke in the Chicago night clubs. They sit much lower than those tall baffles I had. That helped the image appear more natural. Just too many close reflections behind them in both locations. That's why I thought about building boxes and doing away with the back wave. Right now I'm visualizing an L shaped baffle (wedge baffle) with around a 14 inch wing on the inside of the baffles, and open framework around the outer side, top and back. Either use pegboard or mesh wire (like that used on small animal pens) to enclose everything and stuff with poly-fill. I'd have to design the back to be removable, as these old speakers only mount to the back of the baffle board. This would all be easy if my woodshop was up and working, but it isn't. It's all packed tightly in my shed. I'd have to have Home Depot do most of the cutting, which means $$.
At least I have some ideas now to bounce around in the somewhat vacant mind of mine.
Oh yeah, almost forgot. I have a single EV TRXC with a Qts of .667. If I could find another one, I'd use those. Much more suited for a box, like maybe TQWT.