I agree with Hohawaiian. Borax can be too much after a Pro-Cure or similar treatment.
With that said, borax is typically very dry. I will sometimes use a spray bottle of water to "mist" the borax to dampen it before it goes onto the eggs. Simply spread out your borax to be <1/2 thick and mist it. If ya mist it too much (You'll know) then just wait a few minutes for it to dry until ya get the right texture.
X