Wow, just checked out the video, those windows are awesome. I can see why you'd want to play with those designs!
I buy fabric online a lot, and I tend to buy more variety than I strictly need because IME, screen or paper representations just don't work accurately enough to get reliable matches. With buying a few extra fabrics, I've had some amazing serendipity though. I'd rather have an extra FQ or two than fabric swatches...
Oh and a lot of stores will help with color matching. One person from webfabrics.com worked me over the phone to put together some blues that had to be close to each other but work together. It worked out really well for me in that case. If you find the right person to match your creative vibe for the quilt you want to make, it could be superb.