Heat and Filtering (A 2 Part query)

[MrJim]

So - It seems that it is always a given among the "teaheads" that you want to exercise extreme care in keeping the temperature of the tea below 85C - the thoery being that above that morphine converts repidly into pseudomorphine.
When black tar heroin is made, especially out in the bush, they take a garbage can of boiling water and put big blocks of opium and acetic anhydride into it and then boil virousously for hours. The morphine isn't destroyed in that process - In fact it's converted into a more powerful semisynthetic. But SWIM believes that the first part of the process is solely boiling water and opium - essentially poppy tea.
The thing SWIM has been pondering is this. First, swim put some tea on a low heat and then went out to do a quick errand. Long story short, this quick errand ended up taking almost 5 hours. He measured the tea temperature when he got back and it was above 85c. But when he drank the tea later it was one of the best batches he had brewed in quite some time.

This same batch of tea brings SWIM to query 2. He has always used coffee filters - and as anyone using them knows - they take a long time to drip through, and you normally have to resort to twisting clumps of wet straw with your hands to get it all out. Anyways, this last batch was filtered through a sifter. Yep, a flour sifter. It was very dark and thick. But SWIM used about half the tea he had used with coffee filters previously and was blown away by how hard it hit him.
So How important is heat, really?
And what is the limit for overfiltering?