Well, I don't really know what to say... Everything you quoted from WCF and the Canons I agree with. None of them affirm anything about His death in the negative. The Canons without a doubt affirm the sufficiency/efficacy of Christ's death. Owen later changed the concept to simply refer to the value of Christ's sacrifice not to be understood as sufficient for all.

If Calvin didn't mean what he said, and in fact meant the total opposite, perhaps he wasn't a very good communicator? If I believe what Calvin said in Rom. 5:18 and the sufficiency/efficacy position that he agreed with in his commentary on 1 John 2:2, and I agree with Calvin that there is a love God has for all mankind, does that make me a moderate Calvinist? Was Calvin a moderate Calvinist?

Again, I was only trying to reconcile the word "for" from both points of view. I also agree in a real sense Christ only died for the elect because He meant only to redeem these people.

Ursinus:

"Obj. 4. If Christ made satisfaction for all, then all ought to be saved. But all are not saved… Ans. Christ satisfied for all, as it respects the sufficiency of the satisfaction which he made, but not as it respects the application thereof;.. [T]he satisfaction is made ours by an application, which is… two-fold; the former of which is made by God, when he justifies us on account of the merit of his Son, and brings it to pass that we cease from sin; the latter is accomplished by us through faith. For we apply unto ourselves, the merit of Christ, when by a true faith, we are fully persuaded that God for the sake of the satisfaction of his Son, remits unto us our sins. Without this application, the satisfaction of Christ is of no benefit to us."

"[T]he atonement of Christ is sufficient for expiating all the sins of all men, or of the whole world, if only all men will make application thereof unto themselves by faith."

"[F]or the atonement of Christ is for the sins of the whole world, as it respects the dignity and sufficiency of the satisfaction which he made–but [condemnation] arises from unbelief; because men reject the benefits of Christ offered in the gospel, and so perish by their own fault, and not because of any insufficiency in the merits of Christ."

Watson:

"Christ’s blood is a sufficient price for all-- but it is effectual only to those who believe. A plaster may have a sovereign virtue in it to heal any wound-- but it does not heal any, unless applied to the wound."

I would simply like to promote greater understanding among the reformed who conceptually agree with the same doctrines but use some different vocabulary. I say this respectfully, Pilgrim, but I don't think you represent a very balanced reformed perspective. Certainly you are entitled to your opinions, but I think you would do better not to come so strongly against other reformed perspectives, unless you actually think they're heretical.

Probably my favorite authors on the subject are Ursinus and Charles Hodge. Perhaps those writers will give you a better idea of where I'm coming from.