I'd use the blue and the green from the triptych, I think, and vary the shapes and sizes of the cushions. Some bolsters, some conventional. Vary the intensity of the colours, too. Pick up on the orange for the lanai, which will tie the two areas together. You might think of combining orange and purple for the lanai.

I would stick to the colours of the sofas, it is quite bold enough as it is. It looks great btw! As for your other question, I think two bolsters would be enough.

I would love to see a darker purple (tone on tone) here. I think blue or green would be amazing...but may be too much. The sofas are an item by themselves and adding a striking contrast might be too much (the blue would be my vote if you want contrast). A deep purple would certainly work very well and keep the luxurious feel going.

I think black and white striped bolsters would look great, especially with your artwork. I would do 2 per sofa. This isn't the best mockup but I tried...

HI -- With the bolsters and the style of the sofas , it is starting to look very manufactured and stiff looking which end's up looking dated . Don't add more of the same purple in the space and a mixture of different shapes and sizes of soft big comfy cushions would be and look better . Lumbar and square and rectangle and round shapes and with a few different sizes of patterns or some floral . I am not a fan of bolster pillows ( not comfy ), so having others with them would help. I think the black and white color combos is too much contrast to what you currently have . I love the big Art !

I like this yellow/green bolster with the blue stripe. I think it would look fun and eclectic like your space. But, not ALL bolster pillows. Like lefty said...mix it up.

Mystic Valley Traders Oceana - Bolster Pillow · More Info

Fayola Floral Pillow Pink 18"x18" · More Info

I would ditch the bolsters altogether and get a couple of 18" pillows. How many people sit on the sofa's at one time? Do you need 2 or 3 pillows. Go a tone on tone pillow in purple. You have plenty of color in the room.

A huge Thank You to you all--we think we know which way to go now. To answer questions: when we first saw the room (the sofas came with the house) they were side by side with their backs against the window and facing the triptych. That was a tough spot--it seemed all too often people were craning around to see the view (river valley with 4 mountain ranges layered in background). So we moved them to the other side of the room facing the view. But as the lanai is beyond the window, it was too much expanse and too lopsided. Then we tried them facing away from the water lilies (toward fireplace) but the fireplace is 30+ feet away so that was awkward. Thats when we decided they didnt have to be joined at the hip anymore and arranged them like they are now--two conversation areas, one in the room; the other on the 'front row' facing the view. This arrangement also pulls the front sofa away from the window and highlights the sense of indoor/outdoor as the glass is floor to ceiling. (The backs are upholstered the same, so its fun to see that expanse of tufting facing you when you approach the room.) Again, thanks so much for your guidance and great ideas!