Since I can't burst, I'm training with my 4 characters at South Pole at the moment. My highest char is a 102 water, followed by two chars currently at lvl 69 and one at lvl 66.

Their speed (except the water's, she's just the healer and not attacking) is 173-176, I couldn't make their speed exactly the same due to lack of EQ, but I think it doesn't matter. Even when their speed was the same 1-2 lvls ago, they didn't always combo.

This may be common knowledge but I've been away from the game for so long (and I think I used to know this back then), but what combined average level does my team have to be to perform a guaranteed combo? I don't understand difficult math btw so please try keep it simple :)

PS: My team is not using pets (I know, I'll regret it later but meh for now), so it's just my 4 chars with the levels mentioned above.