Adamson vs BShenkin

As we approach the crunch point of the season John and I needed a good result. We nearly got one, with a narrow loss to Barnet Shenkin's team. There was some good stuff, but also a couple of howlers. At the time this looked like the worst of them:

John opened a fairly standard six-card weak three Diamonds and West bid an immediate 3NT. I have a few options, including Double, 4♦ and 4♥. I went for a cautious pass. Time for the opening lead.

You can see that a top Heart works rather well, and we can take the first six Heart tricks. In fact, whatever I lead, declarer only has eight tricks (2 Spades, 1 Diamond, 5 Clubs). So there's not much chance of making the contract. Except...

...I led a low Heart. A grateful declarer grabbed the Queen and claimed nine tricks. Although I normally don't discuss the hands during the play, I felt this was worth an immediate "sorry" to my partner.,

Here are the arguments in favour of a high Heart:

• It won't give away a cheap trick if declarer has ♥Q or ♥Qx in one hand.
• If it's clearly wrong (e.g dummy shows up with good Hearts) I have time to switch to a Diamond.
• On many layouts it lets us defeat the contract with the first six tricks.

Afterwards John suggested I should hae led the King of Hearts, after which he would have given count. I suppose after that I assume he's got three, and play my King expecting him to unblock his Jack. If I start with the Ace instead he would presumably encourage, after which I could either play a low Heart to his Jack or again another high Heart for him to unblock.

But although it seems easy enough for us to take our six Heart tricks I could well see something going wrong.

These are the arguments in favour of a low Heart:

• John might have ♥Qx (or ♥Q) in which case we need a low lead to get all our tricks.
• Declarer could have a stop like ♥Jxx opposite ♥Qx in which case we need to lose a trick, and keep our entries open.
• Declarer could have a Heart suit like ♥QJxx in hand (opposite a singleton) and it needs the second Heart to come through from John's side.

What would you have lead?