Re: A few maybe not so simple questions ?!?
If you use extremely wet and juicy tobacco, the phunnel bowl will keep the juices from running down the stem. The over all quality of the smoke is about the same. You should experiment, and see what you prefer.
I personally like the diffuser. More small bubbles, passing through the cold water, means that the smoke will be cooler. Basic physics. And the diffuser muffles the sound.
A large diameter hose makes for an easier draw, also basic physics.
I have never had much luck with quick-lights. I once bought a batch, and in spite of everything I tried, the smoke tasted like gasoline, I had to toss out the entire batch.
You need to keep the coals down to just enough to produce a moderate smoke. If you have too many coals, the heat will burn up all the flavor, and the smoke will be harsh. Also-keep rotating the coals. Try 12 o'clock, then 3'oclock, then 6 o'clock, etc. Distributing the heat all through the tobacco, will keep the flavor coming, and not overheat the tobacco.
Bowls are expendable. I prefer glazed ceramic bowls, they hold the heat, and are much easier to clean. Try different types of bowls, until you find a style you prefer.