Second and third books

So I've been wondering what to do and thought I would just ask people. With this series I have indeed. Already written the second and third part. Number two is very close to perfect I'm just taking a lot more time in getting a million people to proof read it so I can avoid past mistakes. The thing I want to know, as a new writer is it better just get all three up as fast as I possibly can, or is it better to delay for say six months between each one and do proper launches and all that stuff? Thoughts?