I always smoked spliffs from 13 -16 due to smoking in coffee shops, when I moved back to Australia, my best mate showed me how to do a good ol fashioned aussie mix and taught me how to pull cones. It took me two weeks of being all high and mighty sayin bongs are dirty and so forth, untill I could properly pull the cone through with all the ash 'punch' them proper.
12 years later never looked back and have been smoking bongs daily since 1999. I have no scientific reason why, but I think leaving the ash just tastes terrible and stale and does definitley not get me high anywhere near as much as ripping it right through. I think it has something to do with air flowing through after and pushing it further in your lungs and also giving u a cleaner taste. Just like using a chaser to shot vodka is smooth as, but on it's own with no chaser like the russians do (although they eat olives and cheese often with their vodka) gives you that heavy burn, which can be nice on occasion especially in cold weather.
Still love a good spliff but feel sick from the baccy after one as I don't smoke cigs anymore. Also proper bong use to me is the most efficient way of smoking, and as I only smoke 2 cones max in a sitting these days, often one even, then another one like 2 hours later seem to keep my tolerance on an even keel somehow these days.