Quikcolor for his coat. Leave it on the full 20 minutes. I always put on a saddle pad, and then spray shine product around it while the horse is wet, and then slick the coat down. If you have to put it on under the saddle area to show him untacked, get some super sticky cheap hairspray and spray the saddle/ girth area before you tack up. I love quarter marks, too, either stenciled or brushed in chevron style. I hate chestnuts, so I peel them off and then apply black shoe polish to them.

...and I whispered to the horse; trust no man in whose eye you don't see yourself reflected as an equal.
-Don Vincenzo Giobbe circa 1700