I don't respond often on the forum here but thought I would try and help.
I brought home a demo pair of .7s for a 3-day trial. They sounded great and I decided tto order a pair from the dealer. I had the dealer hold onto them for 3 weeks after they were delivered. Since I live in an apartment they could break them in for me. Got em home and the first week was nothing much to write home about. They were just ho-hum. Didn't understand why the demo pair sounded so good and but the ones I brought home sucked. Thought maybe they weren't broken in completely. So, they were bound and gagged with several layer of blankets and comforters and taped tightly. I then ran them at high levels of pink, white, and brown noise and played music through them during the day. Signal was being pumped through them 24/7. They were being thrashed at around 80 watts of steady conditioning noise according to the meters on my power amp. Listened again after the 10 days so I could get a better read on them. Bass was better. Highs were better but they just didn't invite me in. Nothing compelling about them at all. My son lent me his REL T/5 subwoofer. His is the original, around 7-years old. It was immediately apparent the sub added much needed extension on both the lows and highs, rounded out the imaging so much more, and added much needed presence while expanding the soundstage. But, they still seem like they need a measure of clarity and speed to get them where I think they should be.
Still, I was impressed enough that I bought a new REL T/5x. It will be arriving around 9/20 or so. I will break it in per REL instructions and should have it in place next weekend to change out my son's T/5 starting with identical settings. Stay tuned to see what that brings. Since the T/5x is the third generation of this sub, there are many improvements over the original, according to REL.
Also to add, a life-long friend of mine has a room with similar dimensions. He is absolutely thrilled with his Magnepan LRS (original versions) using a REL T/Zero running them with a Willsenton R8 integrated tube amp. He has it running in the triode mode exclusively with only 25 WPC. Possible the .7 Maggie's may be too much for the size of your room? The room I am using the .7s in measures 24'x13'.
I'll post my impressions of the new T/5x sometime next weekend. Check back here later.
Cheers.