another update: I placed my deposit for a white bass with white pickup covers. Carla has been incredibly responsive and a pleasure to deal with so far. It was about a month from inquiring to getting a spot in the build list. I paid my $1000 deposit and now just have to sit tight until my build happens. My request for white pickup covers is very non standard but their response was a very chill "we'll see what we can do, can't make any guarantees" which is perfectly reasonable given that painted pickup covers tend to be a difficult thing to do right anyway.
So yeah, I'll keep updating this thread as the process goes for posterity's sake and so everyone else who's considering placing an order can see what it's like.