Re: Size of the hookah
The little difference in smoothness most attribute to heat dissipation in the stem. I wonder if there isn't more of some dilution though I can't figure out where the clean air would come from so maybe it is as simple as the heat thing. As to the base the temperature of the water and the surface area are the biggest things to cooling the smoke at that point. The smoke bubbles through basically the same amount of water whatever size the base has but the greater surface area would give it more cooling power and the greater width of the bowl will give the extra stability needed to keep the balance of a taller pipe.
However, all that is moot if you think about how much cooler and smoother the smoke is than even a churchwarden pipe. I have a churchwarden meerschaum pipe and as pipes go there isn't much cooler smoother smoke than that but it doesn't even begin to compare to a Hookah for smooth. It is like every other quality issue with hookahs or anything else will you notice a difference between the bigger/better quality than you do with the smaller/lesser quality well probably but does that make the smaller or lesser one bad or not worth trying? I don't think so. Some might. Usually I think better is the one for me but there are limitations to that. Money is one and hype is the other. Sometimes better isn't so much better as more popular or more consistent. Sometimes you get more reward by going out of the norm and taking a risk.