Here's where my question ended up. The point is this: Nila, level 4, advanced armor, with an army of 105 Imps and 14 Gargoyles, attacks the Medusa Lair (level 8) without any ground units and dies. The question is: how to take it?
All the Gargoyles and 5 Imps are lost. The formation is as described above. Minimum parameter values don't matter: 2, 2, 4, 4...
Instead of 3 Golems, 5 Gargoyles are placed, and that's it, it's easy and simple...