For what I learned lately, one of the biggest problems, after finding the female voice, is the need to use the male voice, when you're not fulltime, because it is clearly sabotaging your throat position and therefore it takes twice as long to achieve a good, passable female voice...
I don't know if it is like this with everyone, but now, when I went fulltime and don't need to use my old voice anymore, the female one became much better in a very short period of time and now I am experiencing no efforts to use it 24/7 and even if someone wakes me up in the middle of the night and I am totally unaware of anything, I still use my female voice... I think the male one is slowly going away and I can't wait to come to the point, where I will no longer have got that male voice position.