I would never do 5 colors for something like the heart shirt. THe Tincture is for the main color of the item. Sometimes we do 2-3 colors, but that's because it's pretty evenly a few colors. Even the explanation of how the Alchemist works shows that generally to get a color like turqouise is when you'd throw two tinctures in. The alchemist is set up to be a chance thing and it likely won't change soon.
We have another thing coming out soon that's similar (as in you know you have a list of things you have to throw in) but not a chance factor (you won't be getting a random item out that fits the thing).
I think instead of paying for things out of the current pool, we could do something like after a year, items retire out of the pool and you can buy those up front (for a specific amount of sP) from Zosi. We could tie it in with levels like if you're level x, you have the opportunity to buy old things from your level and below. I'll talk with about it! :)
(Ideally if we do something like this, I'd like to get a good steady amount of items coming out first!)