I know guys who use 20% from hatching and 1 guy who uses 18% some who start at 30% and drop down to 24%, some who feed 28-30% exclusively, so don't get hung up on protein. The guys who use lower protein say they just grow a little slower, but I'd try to stay at or above 24%. Whatever you do will probably work out just fine.
You should get your eggs, hatch them, raise them on 28% or whatever you're getting and just stick with that. After you've raised a batch, you can decide if you need to complicate things by changing protein levels or adding in meal worms or whatever, but you don't need to do that and it'll only make your life harder.
By now you've asked and had answered pretty much every question it's possible to ask for quail. You know all you need to know at this point to hatch and raise quail successfully. You're as ready as you'll ever be.
Good luck.