Lynn,
I like ~9 AM here in Oregon as the pollen is nice and fluffy and the stigmas are very receptive. However, if the stalks are kept under bags the flowers are available all day.
Pollinated the last flowers on Lion King yesterday. Each stalk had over 200 flowers so I should be able to plant an acre of seedlings from that one alone! My only regret was one of those two very dark purple seedlings that were so admired at the clinic are just starting to bloom. However, I still have flowers of Patent Leather Shoes and Borscht to use. Think all of these combinations could be good.
Kevin