1. You create them via xml. The color pallete that comes with the game is very limited, has only a selection of colors for each faction plus a bunch for relics/asteroids and the like. Aiden made a new color pallete that hase 256 colors to choose from, I use this for my 50 new ship colors added with GST. This is an example of one of them colors:

    <GC3Appearance>
        <InternalName>ST_Krenim_R_Appearance</InternalName>
        <DisplayName>Ship_Color_ST_Krenim_R</DisplayName>
        <!-- Needs to be created with paint.net or the likes if you do not the game will use a plain white swatch and looks ugly-->
        <DisplayIcon>Krenim_R_Appearance_Icon.png</DisplayIcon>
        <!-- Ship Colours. Taken from GradientMap.png (Numbers 0-255, 0 been the top, 255 the bottom)-->
        <DiffuseGradientRow1>60</DiffuseGradientRow1>
        <DiffuseGradientRow2>0</DiffuseGradientRow2>
        <!-- Main Lights Taken from GradientMapLights.png (Numbers 0-255, 0 been the top, 255 the bottom)-->
        <LightGradientRow1>65</LightGradientRow1>
        <!-- Cockpit & Secondary lights Taken from GradientMapLights.png (Numbers 0-255, 0 been the top, 255 the bottom)-->
        <LightGradientRow2>69</LightGradientRow2>
        <!--Engine Taken from GradientMapLights.png (Numbers 0-255, 0 been the top, 255 the bottom)-->
        <LightGradientRow3>65</LightGradientRow3>
        <!-- Materials (These control how much of the materials set in FactionDefs.xml get displayed on the hull of ships) -->
        <SurfaceScale1>10.0</SurfaceScale1>
        <SurfaceWeight1>1.0</SurfaceWeight1>
        <SurfaceScale2>20.0</SurfaceScale2>
        <SurfaceWeight2>1.0</SurfaceWeight2>
        <!-- Engine Colour in RGB -->
        <EngineColor>
            <Red>50</Red>
            <Green>50</Green>
            <Blue>250</Blue>
            <Alpha>255</Alpha>
        </EngineColor>
    </GC3Appearance>

You can choose to overwrite the default pallete with a new one, or simply add a new pallete and point the game to it from GraphicAssets.xml and Crusade_GraphicAssets.xml. Either way addign a new pallete without the default colors in it (there is a combined pallete on the Nexus of default + aidens) will result in you changing all the default colors. Takes a bit of time to go through and set them right.

2. Do not think the UI is built for this. It requires set themes that are in the xml tables, like the example above. To do them on the fly within the game it would have to create xmls and art, just do not think the game is built for that atm.

Thanks!

I still think it would be nice to have a in game drop down menu to select more colors or what not.      I find the lack of selection really flustering at times.

Stardock should just pop all 256 into the base game then. The work is already done.

 I just looked and couldnt find it either

He made a post her eon the forums about it a while back, how I came accross it, cant find that now either.

I find it a bit of a pity that the easy-to-use color sliders from GC II Ultimate were abandoned. Wondering if there's a chance some similar thing would still get implemented ...

I already did this when making my mod 4 months ago, using most of your values (thanks a ton btw!) and doing a whole bunch more of my own (35+). Then over the weekend I did a quick conversion of the 21 new Crusade appearance sets as well. That was right BEFORE I discovered you can no longer use mods in MULTIPLAYER, since you can't edit the game's installed XML in Crusade, thus rendering Crusade completely and permanently USELESS to us, ARGH!!! So freaking pissed about this...

Anyway, I'm just doing a bunch of work now to update my mod for the base game with Crusade uninstalled, and then we'll just start a new game on the same old GC3 2.0 we were using before, sigh. But it doesn't take THAT long to go through the entire GC3AppearanceDefs.xml file, and I actually like the vanilla sets better AFTER they've been Aidanized in most cases, so this is not a high priority for me lol, was just thinking out loud is all.