What should i wear to show a welsh section b?

what do i have t wear to show a welsh section b filly that is 2 years old. I know i have to wear tweed but i dont know if grey tweed is ok or not. I know that my filly should wear either a white halter or a leather in hand bridle which i have and she is chestnut so i dont know what colour trousers i should wear that contrast with them