I find compass 10 reduces losses, even with heros as low as 140 att. Aslong as you send a different mix. As put by Japengo, 2k workers, 2k workers, 2k scouts (you can use 4k, doesnt make that much difference) and 92k or 90k archers respectively. I cant get under 7k losses with compass 9, but have had as low as 4k with compass 10 using this method.