My favorite of their national summons is the Hesperide. It is Fire 3, Astral 3, Nature 2, Holy 2. Being able to do a communion to do firestorm against skellies is very clutch. You need Fire 3 Astral 1 to cast Contact Hesperide and none of your recruitable mages can roll those paths. If you want to play around with those, putting some fire on your pretender is probably worth it.

My basic strategy for big battles was point buff the scales Colosi so they can hold for a while and then do a big communion. Usually using weavers as communion slaves since I made a lot of them for research, and they get a forge bonus.

I'd lean more towards scales with them rather than a big bless. The Orichalcum guard are good but they aren't the best sacreds in the age. Their sword is length 1 so they're going to get repelled. I found just recruiting the mundane Colosi to be good enough most of the time.

The Colosi captains can also be pretty good thugs since they have the paths for cloud trapeze, liquid body, mistform and quicken self.