Themed tournaments - optimum format

I like themed tournaments - in openings I want to explore of course. But having played in a few now, I've reached an opinion on the optimum format.

Usually, these tournaments begin with pools of 4 players (16 x 4) and conclude in round 3. But occasionally, there are pools of 8 players. I think this latter octet-format is far superior for the simple reason that one cancompare and contrast different lines within the same timeframe; hence, studying the opening better