How to change each different colors for some loft surface

Hi,
I 'm a beginner of scripting in gh.
Just I astarted as practice by combining some example files.

I struggling how to change each different colors for some loft surface.

result sees I should change list to integer.
But loft surface is consist of list.
What should I next? thanks in advance.200413_loft col.gh (3.4 KB)