My dear brother, John Conway!
I prefer muddy ground for late cretaceous....late cretaceous was humid!
I believed late cretaceous was a colorful world...colorful flowers and some insects related to flowers (ladybirds, moth, wasp), birds with pretty voice, blue and green dragonfly, slimy
snail, fruit tree exist in late cretaceous....volcano and dust air related to volcano smoke and flowers pollination exist....you can add such things to your pictures for making a better imagination about Tyrannosaurs and ceratops life.....
I hope my advise do not make you angry...it is just an friendly advice from a lonely biologist.....I always like your art very much!
Best wishes for you and your family, your brother always, Amin Khaleghparast (a lonely biologist from Tehran, IRAN)