I find it much easier to dance with a partner who practices in court shoes. Even if the girl spends a couple of weeks leading up to a comp practicing in the court shoes, if she spends most of the time in practice shoes it's not the same. Her balance is definitely altered--I can feel it--and it affects how I have to dance with her. Unfortunately, it's been six years since I've had a partner who practiced in court shoes.
As far as color, my vote is for flesh. Even with a white dress.
Is KatharineH still dancing with Chris, and if so, why did she have to buy a ballgown?
Edit: Katharine, have you considered trying leather court shoes for practice? From what I hear they last a lot longer than satin.