I've visited the site you mention to get colour mixing inspiration, however I found it didn't offer easy selection of shades, tones, pastels, warms & cools.
Also, comparing swatches of fabric to the colours on the monitor are often not easy.
I have one of those small colour wheels you can get at LQS but they are somewhat limited so I went on a major internet hunt for a source for a more substantial colour wheel - one that would provide me with a complete colourway selection - and I FOUND IT.
I've purchased the whole system and it is TRULY FANTASTIC and well worth the cost !!!
Beverly Ash Gilbert was very helpful in answering my pricing questions and as a result, added discount link to her website for those wishing to purchase her entire system.
For those interested in checking out the "Eye for Color" Colour Wheel System, here is the website link:
http://www.gilbertdesigns.net/