Well, making it so that a day was the same thing as several billion years or otherwise making time flow the way you want it to kinda means the same thing to me, personally. If you make a day so incredibly long that if we were there we'd have fossilized and our fossils would be long gone, it would still be one day, true, but, it would definitely account for why chemical tests show things as being billions of years old on Earth. And for us, for all it's worth, it would still be a long friggin time in comparison.
I would never indicate that I know what time means to God for sure, thousand days, one day, or otherwise, but between all time meaning the same thing or nothing, I would go with nothing if you have control and you are immortal. I would think God might be able to see all things or at least know they're happening, because God is all-powerful. But that doesn't mean God has to have any concept of time. In fact, being able to control it would hypothetically give one even less of a concept of time than people who are ruled by the illusion of it.