You should phrase it the same way as the WT does, you know, so if it happens you can say "See, you were warned!", but if it doesn't happen you can say "We never said it was definite!".
Here's an example:
KM 2014 03 p.2 Para 4. 'Will You Seize the Opportunity?'
"Will
this Memorial be our last? We do not know."
Which is a rerun of the WT 1918 Mar 1st 'In Memory of our King'
"Whether the coming Memorial will be the last on earth, we do not,
of course, know"
So if you don't know, why say it? It's hardly a loud warning to save peoples lives, and it's sitting on the fence, playing with words, because you actually have no idea yourself.
One thing is true though. Keep saying that every month, every year "this will be it", and at some point you will be right.
No-one will be listening by then, of course.