LOL Partner has the AK of clubs unless he has J QJ K AJ so what is all this paranoid talk about 41 spades? Even if partner has AK tight of clubs he will either have the HQ or the SJ in which case we still have no spade losers. 7N is the bid that caters to a bad spade split since they cant get a ruff on opening lead. Not just that but sometimes you won't even have to guess diamonds since you will often have thirteen tricks outside of diamonds. In 7N you get to cash side winners and get a count before guessing diamonds. This is a big edge In 7N we often just have 13 tricks without guessing diamonds. The point that partner might "correct" 7D to 7N seems to defeat the point of the problem, Frances specifically told us we have to place the contract. The only legitimate point in favor of bidding 7D is that they might lead a diamond from xx so that increases our chances of guessing diamonds, but given that we have 13 tricks so often in 7N without the diamond suit, and that they might lead a diamond against 7N trying to be passive anyways, I don't see how we can not bid 7N.