I do use Audyn True Copper Max in my custom built 300b monoblocks and Klipschorn crossovers. I wouldn't want to swap anything else in for these, seem to have just right voicing for me. Never tried the True Copper.
I've never been unhappy with any of the copper foil caps I've tried, yes, its likely some work better than others in certain positions. I don't think you can make a bad choice.