I use Osram LIGHTIFY GardenSpot Mini rgb - AAP Version for my GardenSpot Device Handler, this allows for color loop (transition to set color over time), and exposes a Random Hue Property. Then I use the Random Hue Property in CoRE to change the color ever X minutes, and since the Color loop is enabled it transitions to the color over X seconds, it looks really nice.
I created a virtual switch to enable to color loop, I have SmartLighting Smart App turn the virtual switch on at sunset, I have a CoRE Piston that is subscribed to the virtual switch turning on, while the switch it on it checks every X minutes that the switch is still on, if it is it then executes the Random Hue property, I then have SmartLighting turn the virtual switch off at 11:00pm, CoRE then sees that and turns off the GardenSpots.
Osram LIGHTIFY GardenSpot Mini rgb - AAP Version:
Here is my CoRE Piston: