Just one feeding, however many he will eat in one meal.
Lightly dust with plain calcium with no D3 every feeding, dust with calcium plus D3, and a multivitamine every other week.
Be sure to feed (gut load) the feeders with fresh fruits and veggies. You can also use commercial gut loads, like Repashy Bug Burger, Cricket Crack, etc.
Stay away from Fluker's gut loads, both the dry, and the orange cubes.
If you look at the ingredience on their products, you will know why I say this
Also, try to get your cham outside in the natural sunlight whenever possible.
Just make sure they can get out of the direct sun if they want.
I use small reptibreeze cages, with branches and fake vines to take them outside in.