God does, however, have knowledge of how things could and would happen under non-actual circumstances.

Yes, I agree, but what does that have to do with the extent of the Atonement?

God does not prevent a non-elect person from surrendering to Jesus in repentance and faith. Jesus blood is potentially available to cover that non-elect person’s sins. God knows, however, that the non-elect person would never surrender to Jesus under any circumstances, actual or non-actual. Thus, God only provided enough blood to cover the sins of the elect.

But where in Scripture does it say that Christ's blood is "potentially available"? That sounds like Arminian thinking to me.

Also, people do not and cannot seek after Christ unless they were chosen by God before the foundation of the world. God sovereignly regenerates the hearts of the elect, drawing them to Himself and granting them the gifts of repentance and faith. And when I say elect, I do not mean they were elected due to whether or not they would be willing to accept Christ. They were elected solely based upon the good pleasure and will of God.

True godliness is a sincere feeling which loves God as Father as much as it fears and reverences Him as Lord, embraces His righteousness, and dreads offending Him worse than death~ Calvin