Belden outdoor furniture
This language of furniture lends itself to being "built-in"; sturdy and could weather well. I imagine the sectional I have drawn to have a similar vocabulary. Perhaps the seats lift to store cushions. Also, as I have drawn, the back of the couch could double as a planter and a half wall delineating the eating area from the sitting area.
This is a great image to get a sense of what it would be like to soften the edges with plants. The proposed drawing shows the use of plants to soften the south side of the porch, obscuring the view to the rest of the roof. I imagine the planter only a bit deeper than a standard window box, so that the weight of wet soil would not be too great. (This would be verified with Andy.) Also, if you prefer this style of furniture, we could look into creating a cleating system to tie pieces down.
The porch on your roof is rather large. Furniture is a nice way to define smaller outdoor rooms within the larger space. This image is a great example of that concept, using a sectional couch similar to what I have drawn.
Q