I would say the first league is easier. As it only takes a few hours to win it. I would guess like 7 hours a week and you have a very good chance to win it. Of course it depends a bit on how hard the competition is in any given week. And your own SP is an important factor.
For the second league I wrote a post about how much hours you guys at least spend. And I forgot the precise outcome, but I think it was something that you need at least 20 hours a week. In reality it turns out you guys are spending more or less double that time. I really think you do a great job!
In my case it's at least triple that, but I haven't really been keeping track of actual time on Steemit. I know when I get on for any given day and when I shut it down in the evening, but the in between will include bathroom breaks, preparing to eat or going to grab something to eat, eating, and miscellaneous things like laundry, taking out the trash, etc.
But 60 hours is a good baseline, and probably goes up from there depending on the day. This week, I'm hoping to have every day through Saturday to devote to this so, the time might be higher.
For me, it's getting the tuning and then the fine tuning down with the curation. That can take plenty of time, I would think. But once you've got the rhythm, then I can see how it wouldn't have to take so many hours a week.
So, I suppose each has its tricks and work to it.