Since you're starting out, go with a current model controller. It helps from a support point of view.
I have an older DMX Operator and am just really learning to use it. It's not difficult to program lights.
As far as let's say a fade from color 1 to color 2, that's easy. Make a scene of Color 1. Then another scene of Color 2. Use a fade time that feels good for you. When you chance scenes, it will do it smoothly. Honestly, the hardest part will be getting the color right. Use some HEX value charts and convert values to decimal and you should get it through RGB mixing, which is what you're doing with those lights anyways.
I don't have LED anything, so let's say using a bank of 4 Par38's with gels connnected to a DP-DMX20L dimmer page: Red, Green, Blue and Yellow, 1 light each, 1 light per channel, I want to go from each color, but smoothly, like what you want to do. In my case, I set Scene 1 for just the red, then Scene 2 for just the green, then scene 3 for just the Blue, then scene 4 for just yellow. For variety, let's say I use scene 5 for purple, 6 for pink, 7 for orange and 8 for white.(Reality for me: white is 1, but my bad!)
Scenes are programmed. Now, on my DMX Operator, I set a slow fade time, say 4 seconds roughly, then hit the Scene 1 button: RED fades up, from let's say a scene of NOTHING. I hit 2, and I get a transition from red to green as one light fades out while another one fades in. Repeat the process with any scene 1-8, it works the same way, except some of the other colors require multiple ParCans to create the desired color.
In your case, you have a better solution since it's all in the same fixture. The concept is the same, just the method of doing it is much more refined since you're doing it all in one fixture.
I may have to sell all my gear soon due to a recent theft, so perhaps you can get my controller for a good price. But this isn't a marketplace. I just know I'm going to be hungry for a while, and I do mean that in the "there's nothing going in my stomach" kind of way. My wife's been after me to lose weight, so I guess she gets her wish. My new wish my be a burger, an IN-And-Out double double with cheese....
OK, I'm drooling on the keyboard. Go play with your lights and have fun. I have to go eat left-overs.