re: Castle Clash: iOS/Droid Tigerdroppins Guild... iOS boss fight Sunday at 9

I bought $19.99 of gems and got a bunch of heroes which i've sacrificed down to:

60 Executioner
60 Angel
45 Painda
44 Ninja
35 Werewolf
21 Assassin

Before that, I was just using the Executioner and Angel and was destroying bases left and right easily making resources, leveling heroes, and upgrading base with 4 builders. In the process of figuring out which heroes to use and which to sacrifice, I learned more about the game mechanics and realized I had jumped my might up pretty significantly to have 6 heroes (i raid with angel, swap in assassin for arena, currently ranked 549). Now, raiding isn't so easy, so I stopped upgrading anything while I just level the heroes. Currently at 2896 might.

Is there a strategy for minimizing might while leveling heroes? I would like to continue upgrading offensive capability, but is that only going to make my opponents harder? I changed my base design to make it easier to get 100% so I keep a shield more often. At what point is it worth upgrading buildings and dealing with the increase in might?