So, then, is there a "safe" number of seconds that can pass before regen becomes a "problem?"

I'm trying to calculate a multi-player attack on a 14, and the intent would be for the bombs and pikes to hit at the same second respectively, but I have to assume a margin of error with somewhat inexperienced players and crappy lag (when it comes to camp time).

That's where I'm coming from and I just was wondering how safe it is to group waves of similar troops together to save space in the calc. I was doing this already, but I thought I would get a professional opinion on regen.