My first instinct is to play 5 rounds of trumps (to try to induce some to discard a diamond or a spade from 3, followed my 3 rounds of diamonds, the ace of clubs, and a spade to the king, to come down to
which seems to preserve all squeeze chances.
Now on the play of the last heart, we pitch the diamond (unless it becomes high!).
This wins if:
1) West has 4+ diamonds and East has the
♣K (double squeeze);
2) West has 4+ diamonds and also 5+ spades (positional);
3) Either opponent has both 5+ spades and the
♣K (automatic).
I'm having a bit of trouble thinking about all the possibilities - also, say diamonds are 4-3, do we get an indication (restricted choice) about who has the other diamond honour? Trying to get better at double squeezes and math
Edit: Also cashing the ace of clubs seems kind of counter-intuitive now that I look at this again. Not sure.