My blue jacket is a stretch Twill. It is stiffer and a bit thicker then spandex and looks nicer for riding.
My other is a poly spandex. It is lighter weighted- which doesnt present its self as well when I am riding since it can get a wrinkled look.
I have pictures of both with me wearing for halter but not riding. They sit just below the hip when standing and when riding they are worn untucked and sit just over the top of my chaps. I like wearing different clothes so I typically wont wear the same thing in halter then I do in western at the same show- but could if I wanted to.
You can use the same shirt in local schooling shows and even 4-H shows but at higher levals and at Fair you might want two. There are few jackets that can pull off a rail and halter/showmanship jacket but the right one can. I like somthing "dull" that doesn't draw TOO much attention to me.