very interesting speculations...

however, as already pointed out, Boyle's law is certainly useless here. you'd have to use Bernoulli's equation for compressible flow, set up control volumes (or at least control surfaces, it's been too long) and work out velocities, pressures, and densities...

imho there's too many variables here, but the one that's been neglected is fluid speed. my assumptions from the above comments lead me to believe that:

A) you pull approximately the same overall volume of smoke through either large or small hoses

B) it takes you about the same time period to achieve 1 full pull

therefore, the fluid flowing through the smaller diameter hose must be flowing faster. not fast enough to even bother with speculation of laminar vs. turbulent flow affecting flavor, but certainly faster. added on top of that, if you're using a disposable tip, you can think of that like a nozzle, increasing velocity at exit.

maybe there's something there, maybe not...

anyway, what we obviously need is someone with way too much time on their hands to tap a hookah base for a pressure transducer, construct a hose with interchangeable diameter tubing and a pitot-static tube near the mouth piece and let the science-y fun begin