My advice, do whatever you have to in order to get your CFI as soon as possible. There is no more wasted flight time than flying banners. I wanted to continually poke myself in the eye, and it's all done flying crappy airplanes that are maintained JUST well enough to drag rags. Watched three co-workers make off airport landings, one wound up in the surf, two died. A CFI job is MUCH better experience, and you'll probably make more money, and enjoy it more.