Custom GUI colors & removing sell button

Problem #1: I'm looking to add custom colors to the shop on my server however when I edited the hex color 

 

[JsonProperty(PropertyName = "Second Color")]

            public string SecondColor =  "#be2229"; // "#4B68FF";

nothing happened. 

Problem #2: How would I go about removing the sell button like I've seen others do?

I've found the configurable options, however a global option for the sell button would be nice.