BTW it occurs to me that since Solos are worth 20 times a minion of the same level, you could use a Solo swarm for a squadron of 20 minions without changing the level. This might be a good approach for eg Hobgoblin Grunts; if your 3rd level PCs are finding them unimpressive then statting them as a 3x3 Huge Solo swarm would certainly get their attention! This could also be done with say Savage Orcs. It might make sense to stat groups of 20 Soldiers as a 3x3, but Skirmishers etc as a 4x4 to reflect the looser formation. And you could use minions in addition.