With the color of your two I think most any color would look good on them. Helpful, no? :bgrin I did find this and hopefully it will give you more of an idea than I.
"In general, horses are either "redheads" (sorrel, chestnut, red roan, rose gray, dun- horses with red hair) which look especially nice with softer earth-tone shades of sand, rust, brown, peach, and most any green tone, or "brunettes" (bay, black, white, most grays- horses with brown, black, or white hair) which can wear bright jewel-tone colors like red, blue, purple and also the greens well. "Neutral" color group horses include palominos, buckskins, and grullas who can use either the earth-tone or jewel-tone accents, depending on the rider's preferences, horse's coat color, and the horse's markings.
Some horses including Appaloosas, Pintos, and Paints are a little harder to classify. If your horse has more than 50% body white, consider the brunette/jewel-tone colors to contrast with your horse's white coat and avoid a dreary "sand chaps on almost white horse" combination. If your colorful horse has less than 50% body white, use his primary coat color as the determining factor: for example a minimal white sorrel overo Paint would probably look best in the redhead/earth-tone colors.
If you ride several horses, or aren't sure what color horse you may be showing, consider the versatile blue/green color range. From the palest mint to the deepest forest green, these colors look great on almost any horse color, and also carry well from a distance in the show ring. Picture a beautiful teal green shirt with a matching saddle blanket on a sorrel horse and a bay - it's a winning picture either way." -Suzanne Drnec
