These two birds are inherently weak flyers although they don't look as loose as cull ES. The light color, beak and the large head size distinguish this group from the Gazgandi, which is a byproduct of a black Rehani. It might not be that easy for you to tell them apart unless you are raising a pure group of each.
It is advisable to separate this group from The Black Rehanis to avoid mixing. This group is blamed to have ruined the pure Rehani groups by inadvertent mating and diluting their intense black sheen.
The ideal beak setting and head size should be similar to those of a black rehani.