Marching a bari.

IMO, the worst part of marching with a sax is if the make you play the horn completely vertically, exact center of the body, with the neck in line with the bell. That's not natural and causes bad habits. Too many directors are ignorant or just don't give a crap and emphasize the visual effect and uniformity over practicality.

I had problems marching with alto because of this and often didn't actually play much during the halftime show because I didn't want to ingrain any bad habits. Obviously, the problem get bigger as the horn gets larger. Luckily, my college marching band didn't use baris. Not that I would have been marching bari, but I feel sorry for those who would have to, especially if they were forced to position the sax similar to what I had to do for alto.

IMO, it's not a good idea to have baris in marching band.

That said, if your uniform allows you to wear a harness underneath the jacket (ie. buttons down the front where you can stick the clip through) then I would definitely do that. If your uni doesn't allow that then ask your director if he'll allow you to wear a harness over the jacket. Marching band often sacrifices musicality/comfort for the sake of the visual. He might get anal about it and say no but it's worth a shot.

At the university I am at, the Marching Band Direstor will not allow a Baritone Saxophone on the field. I have marched with a Baritone Sax. My advise to you is not to strain yourself at all. If you are in high school, keep the good posture and playing position. If you do not and try to do something your body or the horn will not allow you to do, you run a very real risk of hurting yourself. If your band director is the one forcing you to modify your posture or playing position solely for the appearance and visual aspect it will give and not because of something that is not proper, then do yourself a favor and return to the alto or tenor.

Baritone Saxophones are regal instruments. They fill out nicely and fit well in a big band, wind ensemble, symphonic band, rock band, et c. However, I believe they offer nothing musically to a Marching Band where the force of the drum/percussion line and brass sections overpower everything. If you add a Baritone Saxophone, you might as well add a Bassoon and Contraclarinet.

None of the competitive marching band directors I know ever use a baritone saxophone. I live in the land of the Phantom Regiment and Cadets. I see and hear a few shows a year and have yet to see a Baritone Saxophone in any of the bands.

The saxes are there more for the color and flash that the horns make than they are for the sound. Ditto the clarinets - an instrument that is totally wasted sound-wise in a marching band.

I don't know how I managed to do it, but I avoided all "marching" music save only one brief spell when doing the musical Barnum. Everyone else in that pit orchestra took to the bit of staging that we did like a champ, but I had to learn how to do it from the ground up.

As for other, odd instruments used in marching bands, bassoons were quite common in the several hundred regimental bands employed by Napoleon Ier back in the early 1800's. To paraphrase the old saying, "Six hundred Frenchmen can't be wrong."

In that period, the horn was suspended from the center of the waistcoat (an under-jacket beneath the main uniform jacket) by a ribbon that attached to the ring mounted at the top of the boot joint. The instruments at that time (French system horns slightly smaller than the French horn in use today) were played more in a vertical position as well, at least if period painting are to be believed.

(The button in the waistcoat method was ridiculed by some back in the 1960's, but a historian turned up a period uniform that had been worn by a bandsman (the colors are reversed for the bandsmen, the same as with our Marine Band, which wears the red with blue reversed uniforms from the standard Marine Corps dress blues with red trim) who had been a bassoon player and, plain as day, the appropriate button hole was worn out from the movement of the ribbon.)

I've tried the same setup, and other than the hazard presented by that sharp edged reed at the end of the long crook, there are major problems with balance and intonation. But, it can be done.