Hi Johannian,
" So when I cross-pollinate, do I wait for that flower that I pollinated to close and re-bloom, then I take the seeds and plant 'em the following year? "
For zinnias that you planted outdoors in the Spring, the petals that you pollinated will have set plump green seeds in three to four weeks and you can pull out those petals that have the green seeds attached and immediately plant them. They will come up in 2 to 6 days and grow rapidly to bloom in a month or so, ready for cross-pollination or self-pollination. That way you can get two generations of zinnias outdoors. If you also grow zinnias indoors (as I do and am doing now), you can get another two generations of zinnias indoors. In other words, by growing zinnias both outdoors and indoors,
you can get four generations of breeder zinnias per year. By making hybrids between your hybrids between your hybrids, you can make a lot of progress in a year.
I noticed in the picture of zinnia seedlings that I posted to Kathy above that those seedlings were of a "Needle" strain. I called them that because their tubular petals were needle-like, almost as narrow as pencil lead. (That might be a bit of an exaggeration.)
Variations of those narrow tubular petals can have quite a different look.
Those are reminiscent of some ocean-growing things. The pencil-thin petals can have a variety of looks.
There are other examples of narrow-petalled zinnias that I could show, but you get the idea.
ZM
Variations of those narrow tubular petals can have quite a different look.
There are other examples of narrow-petalled zinnias that I could show, but you get the idea. 
