Ann, don't worry about the size of the seeds. The cultivar that is one of the ones that I plant (Soreya) is a humdinger in size when it grows, but the seed is tiny, very tiny, I am surprised that the end product is so magnificent. Now the Russian giant, the seeds are big, really big.
I have thousands of sunflowers that came up from the vicinity of one of the sunflower patches. I had to thin out hundreds upon hundreds to get the plants to have at least one foot between each one. They must have room to grow, if they are too crowded they will not produce nice plants. I will have to thin them again, to about 2 feet apart, that gives a beautiful stand. YOu will see my pictures of the beautiful grove of sunflowers come later this summer. They are everywhere!!! Beautiful and most wonderful day, we all be lovin' and sharin' this great life. Cindi