It must be nearly eight years for you, Jim. I will hit seven at the end of the month. I agree with Caroline that DMF probably could work again for Mac by some regime, but what is the point of mucking around if you could swap the hassle and clear more quickly with a jab every three months? I'd muck about by varying the dosage, but I have a bloody great bag of the stuff with no use other than as a root rot treatment for succulent plants.
Cheers
Cheers