How to encounter the Tower Tycoon on Pokemon Diamond?

I've been reading around and I know that in order for you to encounter the Tower Tycoon, you need to win in the Battle Tower 49 times. But, I have a question: do you have to win 49 times in Single Battle? Or can you win 49 times in Double Battles or Co-Op? And does 49 battles mean in one of the aforementioned categories, or can they be ulative, winning like 21 battles in Double Battles and the rest in Single? If someone could answer these questions, that'd be great.