I'm glad you posted this! A lot of people here give really bad advice, even those who claim to have the most experience. I know so many people who think bigger lobes = more stretching knowledge so they'll tell you it's okay to stretch quickly because they did. With stretching, time is your friend. Yeah, reaching your goal size is nice, but having healthy lobes is too!
I'd also like to add that if you stretch fast, you build up scar tissue which makes future stretches more painful and difficult. It also makes them harder to shrink if you ever decide to take them out for good.