IF Setterfield [and all of the laughable derivatives of it] were true, the universe could barely have expand AT ALL in its earliest "days" because Setterfield's "theory" requires the universe to be many orders of magnitude more massive than it is now in its earliest days. So massive, in fact, that it would have contracted when it was just a few microseconds old [that's in your fake, "dilated" time. In real time, it would have come back together within a few hundred years of the Singularity.]
Why? Because E=mc2, and if the speed of light was significantly greater in the past, then all matter would have been significantly more massive in the past. And, by the way, as that matter lost energy [because c was decreasing] what happened to the energy? Or, in the [literally] magical world of YEC, is there no such thing as conservation of energy, as well?
There are so many other inconsistencies in the YEC time dilation model that it isn't even worth talking about.
What about a linguistic/logical point of view?
We know that 'day', while generally 24 hours, refers to the time it takes sun to return to the same apparent position in the sky; this is supported by Joshua's "long day" (Josh 10) being referred to as a 'day'. (So, one must accept that 'day' needn't refer to a 24 hour period.)
Yes, the chapter says that there was no day like it before, or since, but that is for the sun [and moon] staying fixed in the sky — something that could not happen prior to the creation of the sun… or Earth (note that Gen 1:2 says the Earth was "without form, and void"). And, still before the sun [or Earth] was formed the first day ends with God called the light "day," and the darkness he called "night." And there was evening, and there was morning--the first day.
So, how would you measure a 'day' by the "evening and morning" when the Sun doesn't yet exist?
Saying that the 'Day' in the Creation have to be 24-hours, is the same sort of worldview-centrism bias as those who claim that the language Adam (and the rest of humanity) spoke before Babel was Hebrew… utterly unsupported assumption tainted by one's own experiential [or philosophical] suppositions.