If you're showing in Showmanship and Trail, it's pretty much judged on you and the completion of the pattern.
Yes, in showmanship you do set up at the end of your pattern, either on the rail or off the rail, but you and your horse have to complete the pattern without undo cueing of your horse. They need to stop and be pretty much set up at that first stop, maybe move one foot, you want it to take 3 seconds or less. Also, backing up, the horse should move back as you move towards his throat latch, you don't want to be over pushing or pulling on your lead. Pivot on the hind, make sure he/she keeps that left hind planted and doesn't move it forward or back.
And with trail, you know not nicking the trot overs, not nicking on the side pass poles, goes over the bridge quietly, open and shut gate without rushing or avoiding. So as long as he is going around quietly and not racing that is all that matters. It's a precision event not speed, so if he goes quietly in his arabian frame that is all that matters. Same if you decide to enter a pleasure class, as long as you are not racing around the arena and passing everyone, he's picking up his change of gates and not being overly dramatic, you will do fine.
I rode a little 14.2 arabian, super flashy and always placed well.