These breast collars are lined and have rolled edges to prevent creating sores. Prices start at $110.
Breeching is important to prevent the saddle from sliding too far forward.
I use buckle covers on the spider straps to prevent the tail from becoming entangled in the buckles
I prefer a (pulling style) breast collar with rolled edges and a strap over the neck to prevent the collar from hanging to low and interfering with the movement of the front shoulders.