it depends on what you want to unlock! i ended up unlocking her star sapphire ring in both because i had points to do it. BUT there are two ways to approach if you unlock in the au first: general WHAT THE HELLness and being confused/scared/baffled, or having their au self "explain" to them (like in a letter or an iPhone video or whatever) what's going on if you wanted to do that. she has her star sapphire ring in both, but has no idea how to use it or what it is int he au ... whereas carol is a queen with it.
i know some people unlock cv first so they can have things in cv-week plots already, but either way is fun.