Hmm not sure if I understand the question- are you asking how to customize the duration of the fade in animation? If so, try changing the code in red below inside the script:
Lower (but above 0) would make it faster (ie: 10), higher would be slower (ie: 200). Another area within the code you can change as well is:
Lower than 10 (but above 0) would make things slower , higher faster. The difference between the two is subtle, but worth experimenting with to see which one produces a smoother result.