If energy is conserved in a rescaling universe, a redshift
of light from distant stars must result as follows.
Imagine a photon of light, of zero rest mass, but of energy
and frequency
being
emitted from a distant star at a time when Plancks constant
was .
When it arrives at earth Plancks constant has become
t is the time of transit for the photon on its journey to
earth, its energy would be
From conservation of energy (no time passes for the photon,
so it is assumed that its energy is unchanged, whereas Plancks
constant, like the gravitational constant, may be dependent
on the surrounding matter distribution and cosmological time).
and the measured wavelength would be
so the emitted light becomes redshifted with time.
and frequency
being
emitted from a distant star at a time when Plancks constant
was 
.
