... Look... there is a standard rule with these things. Boobs are wonderful, sure... BUT.... the hips should always be wider than the boobs.
Still... these two can probably manage arm-level hindboob.
Technically, most women can't achieve hindboob. That glorious state where both of the breasts can be seen around the body (generally under the arms) from behind. But these two... could probably manage it even with their arms flat at their sides.
Subarashii!
Still though. The hips should be wider than the boobs. Always. No exceptions. These two need to put some weight on the hips.