Early morning or late afternoon is the best time for picking flowers in the garden. The moisture is still there (and the bugs are still asleep) and the heat of the sun has not wilted the blooms.
I found this long basket a while ago and find that it is ideal for my blooms as they don’t get squashed together. If I am cutting just a few buds I place them in a small bucket of water as soon as I have picked them, to alleviate the problem of air getting into the stem, but with this quantity of blooms the bucket filled with water would be too heavy to carry.
When I arrange them I have a bowl of water available and cut the stems under the water surface as the flowers last much longer with no “airlock” in the stems.