You have some wonderful advice here. I don't ride often. This is my take, learned as a nimrod on my few horseback hunts.
On one trip I was waring Danner boots with air bob souls. They wanted to stick in the stirrups. Can't emphasize enough the need for good fitting stirrups even if you have to buy them. On the 1st horseback hunt the cook was horse kicked and had to leave camp. They thought he had a broken leg. Was not the case, but he did not return. put a damper on the mood in camp. It can go bad real quick and you need to avoid that drama.
Always approach the horses from an angle (not the rear) and don't surprise them. They often bite each other, and may spook thinking you are another horse. Keep your hands on him if you must side around behind him. Let him know your there and by keeping close he will have less leverage should decide to throw a kick. Be up front with guide on your level of horsemanship. Often these animals are rentals and the wrangler or guide may not know their quirks. I don't want a horse named Tornado, Muy Loco, spooky, Killer or the like. Listen to your guide. When stopping consider removing (carefully) your rifle from the scabbard. Just in case the horse decides to roll. He will try and eat at every opportunity. Don't let him have his way all the time. Control him as if you are in charge. Should the animal be a slow walker, be prepared for a dash to catch up once he realizes he is falling behind. Pay attention to your mount's body English. Alert your guide/wrangler if you suspect a problem, irritation, or possible issue with the tack. In the dark he will tense up just before sprinting up an incline so be ready to lean in and help him climb. I still remember the "sparks in the dark" from a shoe striking a rock. My eyes were so dilatated as we were riding in complete darkness. The flash of light stayed on my retina for 30 seconds or more. Cool memory!
Communicate with the Outfitter, Guide, or Wrangler. Don't be too demanding or a winy pest, but do speak up on what you prefer and what you can expect. Request another horse if you deem it necessary. Don't forget you are paying for this service and your safety and preference matters.
I'm envious of your pending adventure. Have a safe and successful hunt.
LaGriz