No separate calcium at the moment. I have a bag of "chick" oyster shell, but it still look really large for the quail. I also have a couple dozen chicken egg shells that I have ground up, so I will most likely use those when they start laying, then feed their own shells back to them. Still undecided about if I will offer it separate, or if I will mix a little in with their feed each day.
I'd suggest going separate. Then you won't need to worry about getting the amount right, just make sure it's always available, and you won't be straining the organs of your roos as they try to get the overdosed calcium out of their system. I use chicken oyster shell and grind it up in a small blender. It's not very efficient, it's quite noisy and I suspect the blender won't survive doing it forever - but it doesn't really take that much to keep my buttons supplied with calcium, so for now it works for me.