Just remember that if the class calls for Formal Jumper Attire your shirt must have a white collar and cuffs. And there are limits on the color of breeches for Proper Jumper Attire. Although how much this is policed in the jumper ring probably depends on the venue and judge.
a. Formal Jumper Attire. Dark, muted or similar colored, or red (scarlet) coats are required; team or sponsored coats of different colors are also permitted; white or fawn breeches; a white tie, choker (unless the shirt, by design, has the choker built in for its intended use) or hunting stock, and a white or lightly colored shirt must be worn. Shirts must have a white collar and white cuffs. Shirts must be fastened at the neck and tucked into breeches. Boots are required. Half chaps are permitted as long as the color matches the paddock boots being worn. Members of the Armed Services or the police may wear the service dress uniform with protective headgear. (See General Rules, GR801.2)
b. Proper Jumper Attire. Coats of any color are required. Breeches must be light color (white, fawn or canary). Pastel and dark colored breeches are not allowed. Shirts, light in color, must be tucked into breeches and fastened at the top of the neck. Ties or chokers of any color must be worn (unless the shirt, by design, has the choker built in for its intended use). Boots are required. Half chaps are permitted as long as the color matches the paddock boots being worn.
c. Standard Jumper Attire. Coats are not required. Breeches of any color are permitted. Shirts (polo shirts are permitted) must have collars and sleeves (sleeves may be either long or short), and must be tucked into breeches. Sleeveless shirts and shirts with exposed hoods are prohibited. Boots are required. Half chaps are permitted as long as the color matches the paddock boots being worn.