Because many of us follow what others are doing in respect of dosage, in this case B1, I thought I would post that Dr Constantini suggests a dosage for B1 based on condition, onset and weight of the individual. For me his advice was just 2 grams a day, 1 in the morning and 1 at lunchtime.
He also pointed out that if the dosage is too high, it can determine, after an initial improvement, an aggrivation of the first improved symptoms. Then he recommends no B1 for a week followed by B1 at a lower, possibly half dose.
I hope this information helps someone!