Custom white balance from 2 dimmer channels ( shelly rgbw2 )

Hi folks

I’m just getting started with home assistant and can’t get my head around how to solve the following:

I have a 2 channel led strip ( white and warm white ) connected to a shelly rgbw2.
My goal is to be able to switch them on/off, set the dim value and set a ratio ( white balance ) between the two channels.

How could this be done?

Thanks for your suggestions.