This problem is very computational! (ugh, stupid liberal arts degree :)) I think I changed my mind, I agree with your start. The bidding makes it too likely spades are 4-1 to overtake the ♠K, though I would do this with no opposition bidding. After your start I would just try to get back to hand with a club. Yes, there is no legitimate layout where this should work, but the alternative seems worse, since I didn't get Lightner'd.