Sorry, I've never done it. I always finish before they attack.
the only positive am gonna observe regarding the wotr crusade system is it is less punishing and opaque than kingmaker... less punishing by a longshot. kingdom building failure in kingmaker were extreme ez and often were a result o' event proximity to a calendar date.
you may succeed many different ways with wotr army building, but we kept simple:
add marksman (or other ranged)
choose a mage general
is nuances, but do these two things and chances are you win.
we didn't e