Change lighting of keys when another key is pressed

I'm trying to configure my K70 RGB MK.2 so that several of the A-Z keys change color when I hold down the control key, and then I want them to change color further when I hold down Shift+Control.

At first I had accomplished this using profiles and assigning "while [key is] pressed" actions that switch profile, and creating separate profiles for default, just shift, just control, and shift+control. But this is exceedingly clunky, and easily gets stuck if, for example, I press control then press shift then let go of control then let go of shift. The action-stack gets very confused, leading to the profile getting stuck in shift-only mode. I had considered specifying interruption-free execution, but that doesn't appear to work so well, either.

Next I tried assigning solid colors to the keys I want, and having the colors set to only turn on while the key is pressed. This led to clunky lighting-stacks so that I can recolor (or even de-color) keys that are already colored (i.e. control turns Z-key red, shift+control then turns Z-key blue), but that also didn't work optimally.

I have finally settled on a combination of the two: control-key down switches to a secondary profile, control-key up switches back to default. While in the secondary profile, shift-key will recolor keys as necessary. But, again, this is a sub-optimal solution. I would, ideally, like to have an option to add lighting effects to some specific keys that is triggered BY A DIFFERENT KEY (note: the trigger key may not light up at all, or might have its own custom color when depressed).

Please let me know if you have a better solution than profile-switching action + dense stack of solid-color lighting activated by certain keys...