This just came in the mail to me 2 days ago. I measured it fully inflated and it was a solid 25" wide!!
DLP - I have the exact same issues sleeping as you do. Have tried pretty much the same experiments also (including building the "fort" around my pad at night with anything I could find in my pack.
I love my Thermorest pro lite plus womens, but I can't stay on it and it's just not wide enough. Looking forward to trying the new Exped next week while out. I am also willing to add a few ounces to my pack for a good night's sleep.
Just be aware the Synmat UL 7 only has an R value of like 3.1.