What tack is best for starting a wild horse under saddle?

The tack choices for starting a wild horse under saddle should prioritize correct fit, minimal additional stimulation, and the rider's ability to communicate clearly and release completely rather than reflecting the specific equipment preferences of any particular training tradition. Saddle fit is the most critical tack consideration for mustangs specifically, because the conformation of many wild horses — particularly those from Spanish colonial bloodline herds — differs significantly from the quarter horse tree that most western saddles are designed around, with narrower shoulders, a more prominent spine, and a shorter back that can make fitting a conventional western saddle challenging. An ill-fitting saddle on a horse being started under saddle for the first time associates the discomfort of poor saddle fit with the entire riding experience, producing a horse that shows resistance, tension, and behavioral problems that appear to be training problems but are actually pain responses to equipment. A well-padded saddle that distributes the rider's weight evenly without creating pressure points at the withers, shoulders, or loins is the most important equipment consideration, and having a knowledgeable fitter assess the specific horse rather than assuming a generic fit is worthwhile. The halter and lead or a simple snaffle bridle are the most commonly used early riding headgear for wild horses, with many trainers beginning early rides in a halter and lead attached to the halter rings rather than immediately introducing a bit, because the halter provides clear, direct communication without the additional complexity of bit contact for a horse that has never had a bit in its mouth. When a bit is introduced, a simple, smooth, correctly sized snaffle that fits without pinching and provides clear pressure and release is preferable to a more complex bit that requires more skill from the rider to use fairly.