This is absolutely beautiful. I've done similar projects, but with square magazine "tiles" instead of strips to create large landscapes and portraits, and I must say that using strips was genius on your part. I will definitely step outside the square box next time!
I know you want to keep them together, but I think that if you frame them separately in rimless frames, and then hang them slightly apart but still very close together, it could even add to the aesthetic appeal. The rimless frames at IKEA (called "CLIPS
") are super cheap but they are just sliiightly too small to fit posterboard.
Anyway, well done! I hit This Rocks!