You are correct that God's saving designs are penultimate and not ultimate. You are incorrect to assume that it is free will that is ultimate. God's glory is: A Passion for Glory
BTW, answer this question: If free will exclusively determines salvation, then will people burn in hell because Johnny (for instance) doesn't get up off his duff and preach the gospel to Fred (for instance)? Fred then dies the next day where God simply tells him: "Oh, well, at least you have your free will. It is a marvelous gift I gave you, isn't it. Enjoy the Lake of Fire."
Well, I didn't read very much of the article you pointed me to but I'll say that in a sense you are correct. I wouldn't say it is free will that is ultimate, just that the ultimate, God's glory, requires free will. That's what I'm claiming. That doesn't mean you have to believe what I'm claiming.
BTW, answer this question: If free will exclusively determines salvation, then will people burn in hell because Johnny (for instance) doesn't get up off his duff and preach the gospel to Fred (for instance)? Fred then dies the next day where God simply tells him: "Oh, well, at least you have your free will. It is a marvelous gift I gave you, isn't it. Enjoy the Lake of Fire."
I am more in agreement with you on this question than you might have expected. If I viewed this scenario as the only alternative to predestination then I would have a hard time believing in free will. But I think there's another alternative.