I don’t see any way to actually evenly distribute the sprayed cannabinoids into the buds. Not actually going to be able to deposit them into the interior of the flower. Best you could achieve is even distribution on the surface of smaller material (smalls or trim). But there will always be a difference in potency between the interior and surface.
Now you could possibly soak up some cannabinoids dissolved in a solvent with material and evaporate the solvent, this might deposit them into the interior. But that is going to change the texture/taste/look a lot and you can be sure there will be solvent left.
Any d8 sprayed hemp on the market will have differences in potency between the inside and out. Depends on the thickness of the bud and how much someone breaks up the flower if it would matter to the end consumer.