Beginner Gardening: Sunflower species suggestions for bee feeding?, 2 by OniOni

OniOni wrote:
I have been converting acres of pastureland into wildflowers for bee/bird and insect food. With over 250 species of sunflowers, I am overwhelmed with choices. Could someone suggest a yellow, full sun, one flower per stalk, 4 to 6 foot variety with lots of pollen for zone 5, irrigated land? Could you also advise if I should plant the section of sunflowers together or distribute the seed throughout the wildflowers fields? TIA