Re: Your tobacco shouldn't touch the foil
maybe some peoples taste buds are more sensitive to smoke harshness, or another case would be people smoke cigarettes and then are used to the taste of burned tobacco = don't really taste if shisha is burning from touching foil.
personally, when i pack my bowls, a little shisha inevitably touches the foil [i use 2 layers of generic thin foil] and at the end of the session, the top shisha is charred, but never had a harsh pull once during that session. maybe it's because i've been smoking cigarettes for the past 6 months.
like a lot of things, i think whether or not shisha should touch the foil or not is up to personal preference. if the smoke is too harsh when you pack the shisha to touch the foil, then pack less. if you can't taste the difference, then feel free to let the shisha make love to the damn foil underneath the coals for whoever gives a flying f*ck lol