Just made this sectional following the plans from Ana White.
Roughly $900 CAD in materials, $750 of that being the cushions. I used Duvholmen cushions with Jarpon covers from Ikea, accent pillows I found at Home Sense. All 2x4 lumber and I used pocket holes where screws would be visible. Finished with Ready Seal natural cedar.
Quite happy with it overall. It's really comfortable and will last far longer than (and was cheaper than) those plastic weave ones from big box stores.
It does look clean. How does a 90 degree back rest feel? Have you sat on it without the cushions?
It's a bit boney without the cushions, but taking them off also makes it deeper, so you're leaning back more. If you were planning on going without cushions I'd probably put two 2x4s across the back at a slight angle, but you'd probably have to reconfigure how they attach to the arms then.