Your garage is similar to mine, though smaller. After iterating through a ton of designs, I went with the attached combo of Black, Graphite, and Alloy. We kept it simple since the tiles themselves are pretty busy and shift based on the angle of the light.
Agree, give them a call. They're very helpful. I got a sample of the garageflow and it was a bit thinner than the free flow; not sure how it compares to circletrac though.