An alternative way to get Black Cards

On the message boards, people suggest that the way to get black cards is to completely level-up your heroes, build an awesome deck, store hearts from the Daily Gift, and look for matches that are 10 trophies.

You can do this, and I'm sure that lots of people get Black Cards this way. But in terms of maximizing trophies, there's a problem with this.

When you completely level-up your hero and build an awesome deck, you get 45 hearts maximum. Hearts still regenerate at 1 heart per 15 minutes. It costs 9 hearts to play a match and 1000 coins. This means that you can play only 5.3 games per day. Assuming you win all the 10 trophy matches and get a winning streak, you win 14 trophies per match (10 trophies + 4 trophies for the win streak), which means 74.2 trophies per day. Which is pretty good, and if you spend gems to refill your heart meter, you get an extra 126 trophies per gem. And I know that this is what many people do.

However, if you keep your heroes at level 3 or lower, it costs only 1 heart and 75 coins to play a match. You'll pretty much be matched up with only Level 2 decks, meaning only 8 trophies per match (4 trophies + 4 trophies for the win streak). But in one day, you can (theoretically) get 768 trophies! This means that you'll have to constantly play, as your heart meter maxes out at maybe 9 hearts, which means you'll have to play every 2 hours 15 minutes. Even at night. This can be exhausting. Plus you'll have a really weak deck, and it's no fun playing with a weak deck. And you'll lose some of the matches. But even then, you should be able to rack up hundreds of trophies in a day, more than enough to win a Black Card Tournament.

On my phone, I've done something slightly different. I leveled up my heroes to Level 5, except for Jake, who's still at Level 2. This means that it costs me 2 hearts and 125 coin to play a match. Because of my Level 2 Jake, I'm matched with Level 2 decks, which are only 4 trophies per game. But my heart max is 16, which means I need to play only every 4 hours to maximize my trophies. I did this by completing more quests and using an extra hero card from the Algebraic Chest. This gets me about 384 trophies per day (assuming I win all my matches, which I usually do). And this is usually still enough to win me a Black Card in the Tournament.

So, to sum it up,

Maximum level hero -> 14 trophies, 9 hearts, 1000 coins per match -> 75.4 trophies per day, playing every 11 hours 15 minutes
Level 2 or 3 hero -> 8 trophies, 1 heart, 75 coins per match -> 768 trophies per day, playing every 2 hours 15 minutes
Level 5 hero -> 8 trophies, 2 hearts, 125 coins per match -> 384 trophies per day, playing every 4 hours

Hope this helps!