Here's an idea if you want to make a pan set that is easy to maintain & keep clean. I found 'Bead Storage' containers at Wal Mart & Michael's with generic round labels from Staples.
The containers are not air-tight but there are real advantages over the traditional watercolor palette.
The large plastic lid can be used to as a mixing tray & to store colors in use.
Each container has it's own screw on lid. I label the top & bottom indicating contents.
The containers are easy to clean, refill or whatever and cut down on waste.
Here's one filled with Schmincke tube gouache & watercolor. Just squeeze some paint in, then a bit of distilled water & mix with a toothpick.
I've got a bunch of these trays for different brands. They're really clean & economical. They're about 7.00 each but that's a fraction of what you'd pay if they marketed them for watercolors
Just an idea.