How many spades can you sluff on the club suit in the best of circumstances. Please note that a Q J tight in one hand would be neither better nor worse than the 3-3 split that exists, since the 9 would then control the fourth round. And the answer has to be four. The differential in clubs is 5, but one round has to be ruffed, so you've got four sluffs coming, meaning that unless hearts split 4-0, you can sluff all your spades on the clubs. But wait! That means you're not sluffing that diamond loser. Or if you sluff the diamond loser, you can sluff only three spades. So you wind up with 12 tricks.
Do you see the problem? Well, of course you see one problem, which is that hearts are splitting 4-0, meaning you cannot be in dummy ready to run clubs with all trump out. The other proviso, a favorable break in clubs does work out, but that's against the odds also. All of which is to say there isn't a fig's worth of advantage to avoiding the loss of a spade trick, and a lot of risk, which in this case would prohibit that line from working.
Now, let's look at the hand from the closed hand, and you'll see that it works out so simply. You don't need a good break in hearts. You don't need clubs to be any better than 4-2. And the hand unfolds. We must take care of every card in the closed hand, including the knowledge that we'll lose a spade, which we can afford. Hence: at trick two, you must go to the clubs, sluffing a diamond on the second round, and lead a spade. If the King holds, lose a spade -- you risk more than you gain if you say, Oh gee, I can go to the J of hearts and lead another spade toward the queen. Maybe, but suppose West takes that trick and returns a trump! Yes, you would then have one trump in dummy, wanting to ruff two spades! Not a good idea. Whatever the return, assuming the K is captured, you now have the high spade and two little ones, which you're going to take care of by ruffing, no? You've got an re-entry by way of a diamond ruff . . . well, say the return is the Q of diamonds. You ruff, cash the Q of spades, ruff a spade high, back with the 3 of trump, noting the 4-0 split, ruff a spade and lead a club. You've got the top three trump with three trump out and obviously cannot be overruffed.
It works out so easily here where you don't need any great luck. Six-one spades could prove deadly, as well as 5-1 clubs. I guess you can just about always find some chance of bad luck. But you see that you don't need any extraordinary luck in spades and clubs and can indeed live with the worst of luck in hearts! And of course, that's what you want to do, go for the line that requires the least luck.