Might want to use your splatter image to create a pattern.Then you can use it on any layer you like without it having to be a layer
Once it is a pattern you can use opacity,blend modes and it will be scalable.(sizable)
It can also be dragged around WITHIN the layer.
Define pattern is in edit>define pattern(whatever part of the image that is selected or the whole image...it will tile it for you so you might want to make it a seamless tile...(depends on how large it is)
I think PS help has instructions for making them seamless.
Having fun yet?