Clearflight pieds should have a pied spot on the back of their head. The size can vary from the size of a pea to a nickel or more.
The 7 main flight freathers should be pied, but some will have pied feathers that can extend up to the middle of the wing. There can be random normal feathers mixed in on some budgies.
Clearflight pieds should have a belly and chest free from any pied markings like the 2 left pictures below. However, some clearflight pieds will have a small amount of pied patches on the upper chest and throat area like the 2 examples you can see on the right..
Most clearflight pieds will have a few or all pied tail feathers. Some will have normal tail feathers however if the pied gene has not effected them.