@cHIIMEERa
I'm mostly looking to avoid enormous beatings for the lowest level of teams that might be more inclined to leave the tournament because there is no upside, no silver lining, nothing to play for, nothing for them. The way I see things, even the lowest teams in the first division have something to play for despite taking beatings at the hands of NOS and such: they fight to stay in their division. And after all, so what if a team loses all its division 1 games? It will win most of its games in division 2 the next season to make up for it.
If avoiding enormous beatings was the only thing divisions achieved, we'd be better off implementing some sort of mercy rule where if you lead by 6 goals the game is over, or something. Divisions do more than that, while not doing as much in terms of stopping blowouts, I'll give you that. But it's ok as that was never the end goal.
We can also have different sizes for each division but I wouldn't go there as it probably involves personal judgment and I'd like to avoid that like the plague. So to answer your question, I had every division at about the same size of 1/3 of the teams registered to a tournament, potential beatings be damned.