You have to make 4 models, one for each color. Then place them 1 pixel apart on the preview. That will let you see the result. for programming you might be able to make a second model using 4 channel RGBW with 24 strings. Do not make this "part of my display", but you can still use it for sequencing. But you have to be careful on how your channels line up between the physical setup and the model setup. I had 4 colors, 16 strings each before I switched over to all RGB last year and that was how I did it before my move to RGB.
