About 50% humidity is fine. It will take 16 - 17 days. Lock down is at 13 days.
If your eggs were only low on humidity for a while then I imagine they'd be okay. I might go up a hair extra on humidity for a couple of days to help compensate a little. The eggs are so tiny that they can dry out really fast.
What kind of floor does your incubator have? If it has wire, you need to put something in so that they can't get caught in it. Little button quail babies are terribly tiny. They can fall right through 1/2 inch hardware wire, so you will need a solid sided brooder, or one that has wire the size of screen. A Rubbermaid tub is good, but you will need to make a cover for it.
If you go to the top of the quail forum, and click on the first thread, there is a list of important quail threads. One of them has a lot of info you'll need, condensed to a very brief version.
Do you have a blender? You could probably put a bit of food in that, or in a food processor, and grind it fine. I think it might be hard to do with a spoon. You could probably use a mortar and pestle, if you have one, or put it in a bag and beat it with a hammer or a rubber mallet. An thing that you can do to get the pieces tiny is good.
What protein food is your turkey starter? Do you have a
Tractor Supply or Orscheln's near you? If you do, they may have 5 pound bags of
Manna Pro game bird feed. It is in bright yellow bags and is usually near the quail and chick feeders and the small bags of grit. This would be enough for a few button quail for a long time. With 30 adults, mine can go through one of those in a week or so! When they are grown, a pair of them will eat about a quarter cup or so a day of feed. Some of my pairs eat more, but those are the ones where the females are the best layers. Some eat a little less. They'll drink about that much water, too. Mine go through from 1/4 to 3/8 cup a day for each pair. I use little 1/2 cup sized specialty canning jars so I have a pretty good idea of how much they go through. (I had a lot of these left from a project many years ago.) Some of the feed amount is probably from them spilling it down in their bedding.