I know that Season 1, Province 8, stage 7 usually yields about 10 troops. I know this sounds small but it rarely rewards the player with Adventurer's Kits, so it's an easy way to build up troops.
I agree that 8-7 is the best for season 1. In Season 2, 9-10 is also great, particularly for the ascension mats as well troops and recruits. Catch it during an Atlantis event and the energy cost is much lower, and the loot even better.
Atlantis in difficult mode 15-8 .... about 30-35 troops to 12 energy ... during altantis event it yields 49-53 abouts for 9energy +tons of wooden swords and backpacks
You probably want to look here:
What do you think?