We have a sun porch in both of our houses.
Down south, the porch is about 10 x 10 and has one wall consumed by the stucco-faced exterior of the chimney, just like in your house. We installed 12x12 unglazed porcelain tiles. I have a swivel rocking upholstered chair (JCP) and a small black wood end table (Lowes), on which I have the glass based container lamp (Pottery Barn). Some months I also have two parrot cages on wheels out there, and several of my tall container plants such as a ficus benjamina and a scheffelera. On the west wall, I have a rollup bamboo stick shade which cuts the hot afternoon sun, blocks the view from outside, yet allows me to see the outdoors. The only solid wall surface is that shared with the house.

Up north, our sun porch is 17 long x 7' wide with 9' ceilings. We have sliding glass doors on each 7' end wall, and 3 sets of sliders on the other exterior wall. This porch is off our master bedroom.

Furniture in this porch is another swivel rocker and small ottoman (JCP), a floor lamp, magazine rack (homemade). This is setup at the set of sliders facing the street so DH can sit and read and watch the front yard. He could also swivel a little and see the flat-screen TV mounted on the wall of our bedroom. At the next pair of sliders, I have a metal bistro table and two matching cafe chairs with cushions (from a salvage yard), and we frequently have lunch there.
For the back wall and third set of sliders, I have an old repurposed TV cabinet pulled well away from the back wall, yet centered in the other set of sliders. That is where I place my container plants brought inside for the cold weather. I maintain a clear path on the wall shared with the bedroom so we can easily access the slider at the far end of the room....outside is a covered area where I hang my bird feeders and in fair weather we have a couple of lawn chairs too. But at this time of year, the outside chairs are put away. The floor in this sun porch is also tile but 6x6". DH built this room himself, and he put a LOT of molding along the one wall shared with the bedroom. I painted the woodwork and molding detail in a satin white, and the body of the wall BEHR LILTING LAUGHTER. To sort of moderate the cold air coming through all that insulated double glazed glass sliders, I hung floor to ceiling sheers. The panels pulled back via Mardi Gras beads (free in New Orleans) create a real softness to the room.

I include a picture of each sun porch. However, the southern sun porch now has all of my tender container plants big and small in it for the winter, and they are very happy.

...and it is still on the fritz....maybe tomorrow.

If your entry to the porch is in the middle of one wall, will you have access to both ends of the room, should love seats be located at both places?

It is my opinion that the room is too long to consider that setup as conducive to conversation. Too far apart. I would instead consider a chair-and-a-half as the maximum option at one end, and then a light weight and movable chair for midroom. At the far end, I'd consider a high table with 2 or more chairs, like a bar height, to anchor the room. We had ceiling fans at either end of the long room, and one small ceiling fan in our square room.

A sun porch especially needs to be open so you feel relaxed.