Dredge, fair enough if you want to be called a gap-theorist. I wouldn't jump to calling yourself that though, I believe gap theorists may have some additional beliefs that go with being a gap theorist so I wouldn't be comfortable calling myself that.
Though like you I appreciate we do seem to entertain a gap of some sort, in that there is an undefined amount of time between when God says He created the heavens and earth, and the days, which it does not tell us.
The first verse of Genesis strikes me as an exceedingly general statement, in my own words it seems to be saying this; "In the beginning God created the universe and the earth. The earth was formless...etc.."
So it's not so much that there is a gap. For me it's that the first verse says God created the heavens and earth and it does not tell us how long that took, because at the point where the earth was formless and void, is the point AFTER He had created the heavens and earth. Did that creation take 1 second? 1 minute? 1 hour? So before the days of perfecting, the six days, how do we know how long it takes to create a heaven and earth? 1 million years? 1 billion? 100 billion? It simply doesn't tell us how much time it took for God to create the heavens and earth.
It does at least seem reasonable, to me, that the stars and sun may be the creation of our solar system. Perhaps the stars and galaxies were also created when God created the "heavens" in the first verse, because as we know, "stars" would also refer to the planets.
I admit this is all my own conjecture. I myself don't take any stance on this. I am not a gap theorist or an old earther or a young earther. For me the issue isn't important enough to give myself a name that is a defining characteristic. For example I wouldn't call myself a, "T-shirt wearing computer game player". To call myself a "old earth creationist" or a "young earth creationist" to me is like saying, I am a, "stargazing pet owner."
Who cares really? If it took God 1 second that shouldn't bother us, and if it took God 1 million years, again, it may also take someone ten minutes to mow their lawn, or one hour, I really cannot find any great meaning in this, personally. Lol