I used to use individual punched out scallops but adding a few to the outer large scallop circle (Big Shot BigZ die); makes it so much easier, see the pictures to see what I mean.
The "cloud-making gadget":
Ink up your sponge & dab down on the scallop edges - don't swirl or sponge on, dab up & down!
Now move the "gadget" slightly down & twist slightly.
The finished background - now how easy is this!