Why not just buy one online? turbosquid is filled with wrinkly sofas.
https://www.turbosquid.com/3d-models/ettore-corner-sofa-1308922
https://www.turbosquid.com/3d-models/poliform-bristol-sofa-942040
https://www.turbosquid.com/3d-models/restoration-hardware-petite-cloud-track-arm-slipcovered-sofa-1068021
Glad you got it sorted. I have to agree with you that this method of getting smaller details into a model can save some time if you're lucky, but I am always struggling to make it as controllable and predictable as I wish it was, which often leads us to going back to tried-and-trusted UV / displacement methods.
CBR
I got it sorted out. I had to click on Use Deformed Points in vertex map (small tweak) then get the Radius of the splines in Fields correct. The math in the node is just meant to clamp down the radius, sort of as a matte for the round corners to only work in those areas. I didn't perfect it but got close. It seems to be very fickle.