For some reason, I read 3000 instead of 30 000....
Anyway, if the tech levels are close, a 6:1 force advantage will usually win. This is not to say that there won't be surprises - there will. But two similarly armed forces at the same tech level will usually yield victory to superior numbers.
But large American native armies and African armies need a lot of help even with a 6:1 advantage - as it should be. Likewise, the CRTs can change battles dramatically from one tech level to the next. Add a leader, a competent military monarch and a religious morale boost and you aren't exactly dealing in chump change.
If your cavalry light army is crossing a river in the snow while cut off from supplies and fighting a Reformed army led by Cromwell, a six to one lead might not be enough to save you.
