Accessory Color Schemes

I'm a user who just came back after a 2 week hiatus and now I'm interested in acquiring some Accessories.
I've looked up some examples on the Wiki, but most of the pages of each item are generally incomplete, which I understand, but I want to find out which color themes I should go after.
My general color scheme for my knight is a red and gray kind of armor, with the Ruby Bombhead Mask to go as a helmet costume.
Since I'm not exactly familiar with the abilities of Accessories, can something that goes on the front of a Helmet, specifically a Helm-Mounted Display, fit on top of a costume? Will I have to combine that accessory with the costume helm?
And on that topic, which colors would go best with red and gray?
I saw the word Toasty and thought of fire-like colors. Can anyone point me with the right color?
I appreciate your help. Thanks!

The colors are actually shown on the icons themselves. The primary color is the "main" color of the icon.. for example, on something you wear on your forehead, it's the forehead area.
That icon doesn't represent the actual item color though. For example, mohawks use the secondary color for the spikes. So instead of a nice yellow one with "Regal", you get some a pale olive color instead... It doesn't always match the nearby accessories either. You should check the wiki for pictures before trying to make a matching set & figure out if the parts are using the main or secondary color.
In your case you'd have to add a Helm-Mounted Display to the costume you are wearing. But I don't think any of the bombheads support front accessories like the Helm-Mounted Display. They are limited to back and side (I think.)
There are some colors listed here:
http://forums.spiralknights.com/en/node/27984
It seems that the colors have primary and secondary colors. For some accessories, it uses mostly the secondary color. Heavy is usually gray with some dark red but some items like the Heavy Ribbon would be entirely red since it uses the secondary color. Whereas the Toasty one is actually blueish gray. So yeah... a more complete color index will help a lot but that will take some time.