I have used sunflowers decently successfully. I plant a sunflower a little earlier than the tomatoes, and with a spacing that would allow 2 or 3 tomato plants between them. Then a few weeks later transplanted in the tomatoes. Then, when the tomatoes need support, I used the sunflowers as stakes to do the "florida weave" to hold the tomatoes up. Then throughout the season, keep the sunflower leaves trimmed off that shade or are in the way of the tomatoes.
This really only works if you plant in rows, but the rough (slightly pubescent) stalks of the sunflowers hold the string/twine up better than other things (bamboo for example). and they are stiffer and stay vertical better.
I never was convince using (and storing) temporary support for tomatoes. This is the best, and most useful, way to stake them, for me
Hope that is helpful. Give it a try!
