Black show halter always on black or black and white cattle, brown on red or red and white, your choice of black or brown on white, yellow, or grey. If you're in a bind and need to, it's not too big a deal to use the other color, but any color but black or brown leather show halter just doesn't look professional/serious. For the same reasons, I prefer show sticks to be silver or black, but I can tolerate most any solid color if you must. My daughter will use nothing but carbon fiber sticks - they're more expensive but light and strong and don't get bent up like the aluminum ones, but her twin brother says they're too light...
There's nothing wrong with you wearing a little color, but again, try to look serious. Remember you're supposed to be drawing attention to your calf, not yourself.
