On the given auction, it is grossly incorrect to assume the Opponents have a bare minimum. You should assume they are holding 27-28 on average; and will make 10 tricks a good percentage of the time. They are quite unlikely to be going down unless: - you have a good suit and entries over Declarer; or - you have nothing and luck out finding Partner with a good suit in your lea, with entries, despite sitting under the Opponents' strong hand. The latter is unlikely; and the former is ruled out by assumption. Therefore: just lead Fourth best so as to minimize giving anything away. One exception would be: Never lead away from Jxxx. If that's youor one 4 card suit, then it's time to guess a three card suit. The appropriate time for the analysis you are suggsting is on the invitational auction: 1NT Pass 2Nt Pass; 3NT all Pass Now there is a reasonable chance of a set, and one can think about finding Partner's suit when holding a weak hand.