There is no reason to believe that "the space of six days," the language found in the Westminster Standards, means anything but the obvious and normal meaning of the words. There are two issues here to consider. First, the interpretation of the days of creation as being long ages or normal days separated by long ages is a position which arose long after the drafting of the Westminster Confession. To allow men who hold such views today to say that they are in full agreement with the Westminster Standards is to stretch the language of the confession beyond the intent of its authors. As if to remove any doubt as to their understanding of the days of creation, the Westminster Larger Catechism Q. 120 states that one of the reason we are to work six days every week but not the seventh is "the example of God, who in six days made heaven and earth, the sea, and all that in them is, and rested the seventh day."
Second, the language of the confession is a phrase used by John Calvin to oppose Augustine's teaching of instantaneous creation. The Westminster divines were learned men who were no doubt aware of Calvin's usage of the phrase when they chose to use it themselves. In Augustine's position, the six days of creation are a literary device with no literal chronological significance. If the phrase "the space of six days" means anything, it means that the days of creation refer to a literal space of time as opposed to being a non-chronological literary framework. Men who today hold to a literary framework view of Genesis one usually believe in creation over long ages and not in instantaneous creation. Still they agree with Augustine that the days of creation are a non-literal teaching device and not six days in an historical narrative. In this sense, men who today hold to a literary framework view of Genesis one hold to the same general position which Calvin argued against using the very words "the space of six days." To allow literary framework men to say that they are in full agreement with the confession is to go beyond stretching our confessional language. It is to allow the language of the confession to encompass a form of the very position which that language, as previously used by Calvin, was meant to exclude. If we allow this, then how can we say with any consistency that our doctrinal standards actually define our doctrine? We must not become post-modernists for whom language and standards have no fixed meaning.
I’m a six-day creationist ala the Westminster Confession position that you quoted. I fail to see your point in offering Grover Gunn’s comment.