Which diamond to lead?

As East you hold ♠T87  ♥JT9  ♦AQT82  ♣A2 (Mansfield, MA regional, Nov 18, Daylight Open Pairs first session, Board 27) and hear the following auction:

What do you lead?

Diamonds seems like the obvious suit in which to seek tricks, and so the question might transform itself to which diamond do you lead?  I tried the ♦A, which is our “power lead”, meaning it asks partner to unblock an honor if he holds one and to show count if he does not.  Typically, the ace lead would be from a much stronger suit, something like AKJTxx where leader is trying to determine whether to fell the opponent’s doubleton queen (unless partner owns the queen, in which case he will play it under the ace) or to look for partner’s entry to hopefully lead through declarer’s Qxx.  However, the power lead is also useful with a somewhat weaker holding provided leader holds a side entry.

In this case the ace lead was hoped to allow me to continue by playing small if it appeared that the opponents’ diamonds were Jxx opposite Kx or by playing the queen if it appeared that the opponents’ diamonds were Jx opposite Kxx.  Of course, should I be so lucky that partner owns one of the two missing honors and a second diamond, that would be great, too.

This time, the ace lead worked well, as the entire hand was

Dealer: South Vul: #27, none	North ♠  AJ96  ♥  8654 ♦  K65  ♣  Q4
West ♠   432 ♥   KQ732 ♦   974 ♣   T9		East ♠  T87  ♥  JT9 ♦  AQT82  ♣  A2
	South ♠   KQ5 ♥   A ♦   J3 ♣   KJ87653

Partner played the ♦9 (no honor, upside down count), and a welcomed card to see, as it promotes my ♦8, and my ♦Q continuation pinned the ♦J.  When in later with ♣ CA, I could win three more diamonds for a one trick set.

When I saw the hand record and realized that a heart lead would produce an even bigger set, I worried about the matchpoint result.  But when the scores were posted, I was pleased to see us get 13½ of available 16 mps.