No holiday in doubled contract

Consider this deal from a previous Trumps Easter Teams event as the defender sitting West.

Your right hand opponent opened 1H, you passed, responder called 1NT (which, it is explained, may contain up to 11 points), your partner overcalls 2S, opener doubles this which is explained as takeout, you up the ante by bidding 3S, and North ventures 3NT. Here is the auction:

WEST  NORTH  EAST  SOUTH
                    1H
Pass   1NT    2S    Dble
3S     3NT   Pass   Pass
Dble   All pass

Your double at the end (with the West cards shown below) is because you have hearts sitting over opener so that suit will surely not establish for them, and you also hope your double will tip partner off to lead a heart. Partner alas leads the DJ, and this is what you see:

          NORTH (declarer)
WEST (you)            EAST (partner)
 T752
 AJ95
 64
 J92
          SOUTH (dummy)
          
 9
          
 T8432
          
 AQ53
          
 AK5

How do you plan to defend with the West cards? North's diamonds are the king and three small and declarer starts by cashing the four diamond winners, so your first decision is what to discard. You and partner are playing "odds and evens" signals so if you discard an odd card (especially a low odd) that encourages the suit, while an even card is McKenney (thus a low even card asks for the lower of the other two suits, a high even card asks for the higher of the other two suits).

Have you decided what to discard? And have you decided what to play when, later, a low heart is led from dummy? Here is the complete hand:

Dealer South, nil vul.
Contract: 3NT by North
          NORTH
          
 K64
          
 K7
          
 K982
          
 Q864
WEST               EAST
 T752              AQJ83
 AJ95              Q6
 64                JT7
 J92               T73
          SOUTH
          
 9
          
 T8432
          
 AQ53
          
 AK5

On the third round of diamonds, West discarded the ten of spades, McKenney suit preference for hearts. This was a clear signal but, on this occasion, a fatal extravagance. Imagine instead that you as West discarded any other low card, such as the S7. After the four diamonds, declarer takes the A-K of clubs then leads a low heart.

Declarer is marked on the bidding with no more than a doubleton heart, presumably the doubleton king – hence the finesse, scrounging for an extra trick. West must not allow declarer to score that ninth trick. Rise with the HA, then lead the ten of spades to pin dummy's nine (leading a lower spade would allow declarer to duck the trick to East, who would be unable to profitably continue).

True, normally one leads low from an honour but sometimes you need to lead a higher card to trap declarer's honour. Bridge is often about following rules but it can also be about working out the right solution for a particular situation, as here. When defending a doubled contract, you can't afford to go off on holiday – even when it is Easter!