Also with vaj/-mo' (at least to me), while some uses could be done with
either one, I still see a difference.

"I saw the signal (that warns that the enemy is coming), so I got ready
to fight."
You could use either vaj or -mo'.  I would use vaj.
I don't get ready to fight /because I saw the signal/.  I get ready to
fight /because the enemy is on the way and battle is about to begin./
But this part could be just me.

I think that's just you. Grammatically, you get ready to fight because you saw the signal which tells you that the enemy is coming.

ghum vIleghpu'; vaj jISuvrup
ghum vIleghpu'mo' jISuvrup

In both cases, the first clause is the cause of the second clause, no matter how indirect an explanation of your behavior that cause is.

You could also say you get ready because you know the enemy is coming, but this would be expressing a different concept.

-- 
SuStel
http://trimboli.name