There are 2 cases:
You vary the parameters of the standard model and look (theoretically) what happens. Even question is theorectical, it is very important in understanding of the cosmology and life in our Universe.
But you can't change h in the same way you can change anything else. Of course, you can ask 'what happens if laws of our Universe were absolutely different. But it is a major change, not a minor change. (Max Tegmark call it level IV multiverse).
Again, h is not a constant or a parameter. Example:
We measure distance in meters, and surface- in square feets. Then the formula would be (h, w are height and width in meters):
S = 10.82 *h*w
The number 10.82 is a result of a bad choice of units. The same as h, G or c! In natural units the formula is
S = h*w
And the parameter simply dissapears. The same as h,G and c. So by asking 'what if h would be different' you are asking 'what if instead of 10.82 it would be 5.41' But it means that in natural units it would be
S = h*w/2
It is not just a different parameter, but different geometry and mathematics.