[ArcLight]

Spoiler

Assumption:

1. RHO opened 1 Club. I assume he does not have 4 clubs and 4 diamonds since he would probably open diamonds, and his Clubs aren't super (like AKJT in which case he might open 1C).
Maybe RHO is: 3=3=3=4, and LHO is: 2=2=5=4

3=2=3=5 :: 2=4=5=2 - LHO would make a negative Dbl.
If RHO had 5 clubs, LHO might be less likely to raise with just 3.

2. You have 5 spade tricks (4 + club ruff) Even if you take 2 hearts, you need another. That means the dime ace must be with RHO. (I don't think an end play will work.)
LHO has shown up with
Dime A x x x x
Club K Q x x

Its likely RHO has the heart Ace, Club A J (else west would have played it on round 2, and east would not over take), Spade J, Dime Q.

The key is who has the heart Jack.

Since I am playing H to be 2-3 and its more likely RHO has the J I play a heart to the king losing. Later enter dummy via the Dime K. Play a heart to the 9

[y66]

RHO did not open 1N. So play him for 12-14 including AJ of clubs and LHO for 8-10 including KQ of clubs.

Think RHO is 2434 or 2344 tho he might have opened 1D if 2344.

3 top spades ending in dummy then finesse RHO for HJ.

[Vilgan]

I'm confused as to why it is impossible for RHO to be 3433. Its unlikely, but certainly possible given the bidding.

At the table I would likely play the AK of spades and lead a heart towards the K. Not sure if leaving the Q of spades as a non roughing entry is "necessary" but it seems like a good idea anyways in case I get hearts wrong and lose 2 of them. Even if LHO has Jx of hearts and Txx of spade (although that isn't the case) I think I still make as they cannot get back to RHO's hand to rough a heart continuation.

Be interesting to see what the technically correct way is. This is just how I would approach the hand.

[1eyedjack]

Spoiler

I think that there is room for either oppo to have the key card (Heart Jack). If you take a losing H finesse into West's hand you are exposed to a Diamond switch through the King. If you take a losing H finesse into East's hand he cannot profitably attack Diamonds. Furthermore, superficially you can afford to lose to the Heart Jack and make 3 Heart tricks, 4 trump tricks and a ruff, as long as you don't lose 6 tricks beforehand.

The danger in finessing Hearts through West is the possibility of East being able to hold up the Heart Ace and cut you off from the Hearts by forcing you to ruff a club in dummy before the Hearts are high.

You could counter that threat by drawing just two rounds of trumps with the AK, then run the Heart 9. If East wins with the J and continues Clubs, then you ruff in Dummy and continue Hearts before drawing the last trump. East wins the third round of Hearts but now if he continues Clubs you can ruff it in hand and you still have a trump in hand to cross to the Queen, thereby drawing the last trump and enjoying the Hearts.

This line is not without risk of a Heart ruff, which might beat the contract when the simple route of drawing trumps and successfully guessing the location of the Heart Jack would have worked. So I am not convinced that the solution is clear-cut. We have been told in the OP that west started with Tx doubleton trump, which adds safety to this line. In real life of course you will not have that prior information.