I have some cute orangey-yellow ones that are short.I let them set then cut off seedhead,but the others I've been snipping.Its taller was a spring
/fall fling item(and was suppose to be a marigold/calendula seed
.)I've grown an orange one like my orangey-yellow& really loved it.I hated the ones I grew last year.I don't like the tall ones& when we get boiling hot down here...the tall ones look crappy,while the shorter ones it don't effect.
choose a few stems for seeds
,then keep the rest cut..thats what I do with my zinnias.