I'd be inquiring about their agreements here. My partners and I have the understanding that the void is "useful" here, i.e. not in partner's suit. If they have the same understanding, the the A♦ should be safe, then wait for the heart trick.
There is a VERY good chance the opps are going down but before you bring out the x card ask yourself a couple of questions 1. What is your plan and will the mysterious void wreck it? 2. r u more likely to x with a trump void or a trump stack? So after meekly putting the x card out of your mind since there seems to be little benefit to risking a small slam for a +50 what to lead? If north has a dia void (with our AQ coming down in no time) a spade lead seems needed. I am also concerned with a side suit with north allowing a short suit pitch from the south hand. The odds seem slightly higher spades are short somewhere since they were never bid so I am going to hang my hat on the spade ace and be prepared to conveniently ignore this hand when I write my next book (yeah right) on opening leads. Oh and as an afterthought apologize to poor partner:))