A pink or white muzzle may predispose the horse to rubbing. These are the horses that generally need sun block in order to avoid sunburn
(Please give details)
For instance, is he heavy on the forehand does he come above the bit is he resistant in downward transitions does he have tongue evasions?
e.g. Monty Roberts, Parrelli etc
(Single jointed, lozenge, French Link, Waterford, Dr Bristol etc)
(Loose Ring, Eggbutt, D-ring, Full Cheek, Pelham, 3 or 4 Ring etc)
Draw reins, pessoa, Bungie etc.