[Agema]

I think what you've overlooked are the ordinary magisters. They look bad as no paths are guaranteed. However:

You've got 50% E, 50%A, 25%S. That means 6% have 3 paths, 31% 2 paths, 44% 1 path, and 19% 0. In research terms that means (0.06*5 + 0.31*4 + 0.44*3 + 0.19*0) = 2.86 each on average. That's not bad for 70gp, certainly much more efficient that Magister Arcana, and a similar research:gold cost many other nations will be paying. Magisters aren't going to die of old age, 25% can be communion slaves, and if you can't think of anything better to do with the 19% that have no picks, you could always save yourself the upkeep by suiciding them into indies or someone's PD.

Your magic and troops are capable enough for the early and mid game. Fairly obviously, you want to think about making your pretender capable of accessing late game power. You only need D2 to be able to eventually forge and summon your way to D6. As you can make astral caps and crystal coins already, Just S3 can get rings of sorcery then rings of wizardry, to S6 (and D8).

You won't be needing many of your S and D gems as your battle mages won't need them, so you can afford to splash lots on summoning and forging.