I made custom angled trumpet moutpieces which allowed me to have a better horn angle in marching band. Typically my embouchure while playing was angled downwards, which in marching band made it difficult to keep my horn angle above parallel with the ground. By angling my mouthpiece, I was able to maintain the proper horn angle without leaning my head back super far.
I made the mouthpieces using a vise, 2 small metal cylinders and a large metal cylinder. By wedging the smaller cylinders on the edges of the mouthpiece on one side and the large cylinder in the middle on the opposing side, tightening the vise induced bending about the large cylinder in the middle.