I will tackle almost anything, and after getting two seat bottoms from GAHH, attempted it, and abruptly aborted it after getting the cushion out. I found an upholstery shop that MB uses and they did both for $200, and got it back the same day.
You will find MB does not do hog rings, they have an inverted lip that the material pushes into with a stiffening ring. They also use some plastic ties to hold the cushion onto the springs in the frame