My friend wants to purchase one or the other, and we're having a little argument. He thinks a smaller opening will be higher pressure and you'll take in more of the bowl (with less escaping), and I think a bigger opening will be better and less will escape. I personally think with a smaller hole, as you're inhaling, more excess smoke will escape from the bowl itself.
Thoughts? Does anybody know for sure which waste less weed to put it in layman's terms?
[EDIT]
When I say opening, I'm talking about where you place your mouth. He prefers the type where you wrap your lips around it, and I prefer the bong-type openings where you put your lips inside it.