So i'm planning an endeavor that the explorers will take up a crusade to take back a planet fallen to chaos forces. In the battlefleet koronus book i've read through the acquiring troops rules, but it seems like there should be a difference rules wise from mustering troops, getting them from a planetery governor or hiring merceneraies. Has anyone made house rules about this at all?

I'm also wondering, since this will be my first useage of the mass combat rules, if there's a good way to limit the battle. as in, the total power of units fielded is 100 or something like that. Just want to ensure the battle is fair and doesn't get ridiculously long and complicated. I'm hoping to have 7-10 units on each side, but i want the explorers to use a variety of units, not just the strongest ones.