ha ha you bring up the age old argument...
I'm in the flushing camp because i use semi / non organic nutes... I don't flush organic, no need (I do the odd organic grow now and then)...
I have looked into this loads (I do produce a product for medical patients), I'm not a botanist so I have done my own experiments... near on a couple of years ago I blind tasted a group of friends over a period of time... all preferd the the flushed plants over the non flushed every time... they had no idea what I was up too, they haven't got clue about growing any thing so there personal opinions / ideology's could not taint the test... I also told them i was pheno hunting so they though it was diffident plants in the jars (they knew it was the same strain)... ha ha little did they know it was the same clones in both jars... every one thought they was smoking different plants, all wanted to break down the individual flavors and taste like they was testing wine... all chose the flush plants in the end with most saying the non flush tasted in their words "a tiny bit green / bitter"... Now i know this is not the best of experiments as there are so many variables like drying time, RH, etc etc etc... but it was good enough for me.
I can now tell if I haven't flushed for long enough ( I cure all my bud for minimum of 2 months and that's after the trim and burping)... There is a very subtle taste I can pick up on now if I don't flush for long enough... I will sat this that it's only with my long term strains that I pick up on it. Takes few grows on the strain to figure out it need a more flush that some of the others
Did I say I mix no tobacco in my joints, pure all the way... I also don't go by the white ash, to many variables to cause white ash... How tight you roll a joint is one... I think the cure is more important to white ash that flushing
I have read the opposing camp pappers and arguments but I have to say this the only research they have shown comes from the Tobacco / Food industry... not one paper yet written about it on cannabis... just years and years of experience by a massive grow force around the world that have come to the same conclusion
I would argue back and say that there some science behind it now, people are finding out why and if you talk to 2nd / 3 rd generation commercial growers they will be deep in the flush camp...
If you want more proof I will let green gene tell you why... 3rd generation grower, this man know his apples more than most... I owe my system to him, he has been the biggest influence in how G'room operates.