Then I sometimes use this internet tool to check how the different proportions might look in actual pictures. It's called TinEye Labs Multicolr Search Lab, and it searches Flikr creative commons images for photographs that match your chosen colours and proportions thereof.
Below is the search I did based on the proportions of colour in the above mix. Whoa! Look at all that orange, and I can now see that the orange is about the same tonal value as the pink, so there is less tonal contrast than I might like. (Click on the image and that should biggify it if you need a closer look.)
The photo above and the search results based on proportions below. This reminds me of sunsets and I like the large proportion of light - some nice contrasts.
Above is the photo, and below is the search with the roundabout proportions. Lots of pinky purple coming through here. More restful perhaps? And once again, less tonal contrasts.
And below is the search I did with equal colour proportions. I find it a bit messy, or perhaps busy is a better word, no focal colour that draws me in.
So how do you play around with your colour palettes? Do you rearrange your stacks to get an idea of how fabrics play with others in your chosen scheme? And do you rearrange proportions to see what different looks you can get?