It may sound that the so-called organ experts can do miracles for you, but they can't.
I may advice for 3 correct repetitions in a row of any fragment that you practice but it depends entirely on your situation because there are many variables to consider - your technical level of ability to play the organ, the characteristics of the organ, the piece you are playing etc.
You may need just 3 repetitions, or perhaps 5, 10, 20, or even 100. Only you will know.
The best learning is always experimental self-discovery - you have to fail until you succeed.
It's that simple.